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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
THE PARAMEDIC REVISION GUIDE
The Paramedic Revision Guide delivers a one-stop reference for paramedic students, paramedicine educators, and practicing paramedics. Designed to take the mystery out of paramedic education, the book provides a solid foundation of understanding in crucial areas of paramedic science and practice, including practical skills, research, anatomy and physiology, pharmacology, and medical emergencies.
This guide furthers readers' understanding and practice of emergency care, and includes:
- A thorough introduction to paramedic anatomy and physiology, including anatomical and medical terms, cellular biology, and pediatrics
- An exploration of practical skills for paramedics, including scene survey, airway practices, basic life support and defibrillation, burns, and head injuries
- Practical discussions of medical emergencies, research and evidence-based practice, and the ethical and legal considerations for paramedics
- An analysis of pre-hospital trauma treatment, including the physics and physiology of trauma
The Paramedic Revision Guide earns a place on the shelves of all paramedic students and educators who need a comprehensive handbook full of succinct and easily digestible information, ideal for exam preparation and quick reference.
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Seitenzahl: 417
Veröffentlichungsjahr: 2021
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Table of Contents
Cover
Title Page
Copyright Page
Disclaimer
Preface
1 Paramedic anatomy and physiology – 1
Anatomical and medical terms
Questions
References and Further Reading
Cellular biology
Quick Questions
References and Further Reading
The nervous system
Questions
Questions
References and Further Reading
The respiratory system
Questions
Quick Questions
References and Further Reading
The cardiovascular system
Questions
The heart
Questions
Electrocardiogram (ECG)
References and Further Reading
The gastrointestinal system
References and Further Reading
The endocrine and exocrine system
Questions
References and Further Reading
The renal and urinary system
Questions
References and Further Reading
The skeletal system
References and Further Reading
The muscular system
References and Further Reading
The integumentary system
Questions
References and Further Reading
Paediatrics
References and Further Reading
2 Practical skills for paramedics – 1
Scene survey
Quick Questions
References and Further Reading
Bleeding
References and Further Reading
Airway
Quick Questions
References and Further Reading
Basic life support and defibrillation
Quick Questions
References and Further Reading
Shock
Questions
References and Further Reading
Wound classification
Quick Questions
References and Further Reading
Fractures and dislocations
References and Further Reading
Splintage
Quick Questions
References and Further Reading
Spinal injury and immobilisation
References and Further Reading
Head injuries
Quick Questions
References and Further Reading
Patient assessment
References and Further Reading
Trauma assessment
References and Further Reading
Glasgow Coma Scale (GCS)
References and Further Reading
3 Pharmacology – 1
Pharmacology
Pharmacodynamics
Pharmacokinetics
Administration
Routes
Time taken to reach systemic circulation
Paramedics, medicines and the law
Yellow card scheme
Questions
References and Further Reading
4 Medical emergencies – 1
Anaphylaxis
Asthma
Chronic obstructive pulmonary disease (acute exacerbation)
Hypoglycaemia
Myocardial infarction
Seizures
Questions
References and Further Reading
5 Research and evidence‐based practice – 1
Evidence
Quick Questions
References and Further Reading
Research
References and Further Reading
Developing a research question
Questions
References and Further Reading
6 Ethical and legal considerations for paramedics
Accountability
Types of accountability
Regulation
Ethics
Capacity
Consent
Negligence
Quick Questions
References and Further Reading
7 Paramedic anatomy and physiology – 2
Respiratory physiology
Questions
References and Further Reading
Cardiac physiology
Questions
References and Further Reading
Neurophysiology
Questions
References and Further Reading
Renal physiology
Questions
References and Further Reading
Pregnancy and maternity
References and Further Reading
8 Practical skills for paramedics – 2
Cannulation
References and Further Reading
Intra‐osseous needle placement
EZ‐IO® needle size
Technique for EZ‐IO® insertion
Quick Questions
References and Further Reading
Endotracheal intubation
References and Further Reading
Needle cricothyroidotomy
References and Further Reading
Needle thoracocentesis
Quick Questions
References and Further Reading
Patient assessment
References and Further Reading
The 12 lead ECG
References and Further Reading
9 Pharmacology – 2
Cell signalling
References and Further Reading
10 Medical emergencies – 2
Hyperglycaemia
Pulmonary embolus
Acute left ventricular failure with pulmonary oedema
Hypothermia
Questions
References and Further Reading
11 Research and evidence‐based practice – 2
Quantitative and qualitative
Research terms
Randomisation
Sampling
References and Further Reading
12 Practical skills for paramedics – 3
Decision theory
References and Further Reading
Patient consultation
Quick Questions
References and Further Reading
Ear, Nose and Throat (ENT) assessment
References and Further Reading
Eye assessment
References and Further Reading
Respiratory assessment
References and Further Reading
Cardiovascular assessment
References and Further Reading
Musculoskeletal assessment
References and Further Reading
13 Pre‐hospital trauma
Physics in trauma
References and Further Reading
Physiology of trauma
Quick Questions
References and Further Reading
Penetrating and blunt force trauma
References and Further Reading
Spinal trauma
References and Further Reading
Fractures and burns
References and Further Reading
Traumatic cardiac arrest
Quick Questions
References and Further Reading
14 Pharmacology – 3
Further pharmacokinetics
Renal failure
Liver failure
Elderly
Children
Questions
References and Further Reading
15 Research and evidence‐based practice – 3
Additional research terms
Performing a search
Quick Questions
References and Further Reading
Answers
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Denoting the difference in neuroglia between the central and periphera...
Table 1.2 Effects of nervous system innervation on the sympathetic and parasympa...
Table 1.3 Components of the cardiovascular system.
Table 1.4 Role of the blood.
Table 1.5 Correlation between blood group and blood antibodies.
Table 1.6 Flow through the heart.
Table 1.7 Components affecting wound repair.
Chapter 2
Table 2.1 Effects of anaphylaxis on different systems.
Chapter 5
Table 5.1 Levels of evidence.
Table 5.2 Grades of recommendation.
Table 5.3 Examples of research terminology.
Chapter 8
Table 8.1 Flow rates.
Table 8.2 Position of the chest leads.
Table 8.3 Placement of right‐sided ECG.
Table 8.4 Placement of a posterior ECG.
Table 8.5 Depicting the regions affected if there is associated ST segment chang...
Table 8.6 Rough correlation between areas of ST segment changes and coronary ves...
Chapter 11
Table 11.1 Research terms.
Chapter 12
Table 12.1 The CAGE assessment tool.
Chapter 15
Table 15.1 Research terms.
Table 15.2 Example PICO question.
Table 15.3 Example synonym table and Boolean search strategy.
List of Illustrations
Chapter 1
Figure 1.1 A labeled representation presented in the anatomical position.
Figure 1.2 Labeled nine regions of the abdomen.
Figure 1.3 Labeled diagram of a cell.
Figure 1.4 Simplified depiction of the phospholipid bilayer of a cell wall....
Figure 1.5 Labeled diagram depicting the regions of the brain.
Figure 1.6 Simplified depiction of neurons.
Figure 1.7 Diagram demonstrating the electrical response (action potential) ...
Figure 1.8 Visual representation of propagation of an impulse along a cell m...
Figure 1.9 Visual representation of the layers of the spinal cord.
Figure 1.10 Simplified diagram of a spinal reflex arc.
Figure 1.11 Diagram denoting the facets of the peripheral nervous system.
Figure 1.12 Labeled diagram of the upper airway.
Figure 1.13 Labeled diagram of the respiratory tract.
Figure 1.14 Example spirograph annotated.
Figure 1.15 Pressure changes during inhalation and exhalation.
Figure 1.16 Gas exchange within the alveoli.
Figure 1.17 Simplified clotting cascade.
Figure 1.18 Labeled heart.
Figure 1.19 Simplified diagram of fluid dynamics.
Figure 1.20 Labeled conduction system of the heart.
Figure 1.21 Representation of the proportional time takes during a cardiac c...
Figure 1.22 Example ECG complex.
Figure 1.23 Renin‐angiotensin cycle.
Figure 1.24 Labeled example of a nephron. Source: Mori et al. (2016). Diuret...
Figure 1.25 Representation of the axial and appendicular skeleton.
Chapter 2
Figure 2.1 Jaw thrust.
Figure 2.2 Head‐tilt/Chin‐lift.
Figure 2.3 Sniffing the morning air position.
Figure 2.4 Neutral position for paediatric.
Figure 2.5 OPA insertion.
Figure 2.6 NPA insertion.
Figure 2.7 iGel insertion.
Figure 2.8 Two‐handed technique with BVM.
Figure 2.9 Back blows.
Figure 2.10 Abdominal thrusts.
Figure 2.11 Anterior – anterior.
Figure 2.12 Axillary – axillary.
Figure 2.13 Anterior – posterior.
Figure 2.14 Vacuum splints.
Figure 2.15 Kendrick traction device applied to a manikin.
Figure 2.16 Pelvic immobilisation flow chart.
Figure 2.17 Pelvic binder applied to a manikin.
Figure 2.18 Representation of Coup and Contra‐coup injury.
Chapter 8
Figure 8.1 Grades of laryngoscopy.
Chapter 9
Figure 9.1 Depicting cell signalling.
Figure 9.2 Cardiac nervous system and drugs.
Figure 9.3 Respiratory nervous system and drugs.
Chapter 13
Figure 13.1 Lethal triad.
Figure 13.2 Le Fort 1.
Figure 13.3 Le Fort 2.
Figure 13.4 Le Fort 3.
Guide
Cover Page
Title Page
Copyright Page
Disclaimer
Preface
Table of Contents
Begin Reading
Index
Wiley End User License Agreement
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The Paramedic Revision Guide
David W. Thom
Specialist Practitioner ‐ Critical Care, Dorset and Somerset Air Ambulance, Henstridge, Somerset, UK
This edition first published 2021© 2021 John Wiley & Sons Ltd
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
The right of David W. Thom to be identified as the author of this work has been asserted in accordance with law.
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Library of Congress Cataloging‐in‐Publication Data
Names: Thom, David W., author.Title: The paramedic revision guide / David W. Thom.Description: First edition. | Hoboken, NJ : Wiley‐Blackwell, 2021. | Includes bibliographical references and index.Identifiers: LCCN 2021008650 (print) | LCCN 2021008651 (ebook) | ISBN 9781119758068 (paperback) | ISBN 9781119758075 (adobe pdf) | ISBN 9781119758082 (epub)Subjects: MESH: Emergency Medicine | Anatomy | Physiological Phenomena | Emergencies | Pharmacology | Evidence‐Based PracticeClassification: LCC RC86.8 (print) | LCC RC86.8 (ebook) | NLM WB 105 | DDC 616.02/5–dc23LC record available at https://lccn.loc.gov/2021008650LC ebook record available at https://lccn.loc.gov/2021008651
Cover Design: WileyCover Image: © Stone’s Throw Media/Shutterstock
Disclaimer
The information included within this book is written with the best intention and knowledge at the time; however, some of the content may be out‐of‐date at the time of reading. Local guidelines, procedures and national variation may affect the application of this text in practice. Local guidance should be adhered to in line with your employer's policy. The author accepts no responsibility for the actions or omissions of individuals. Practise only within the scope of practice as designated by your employer and professional registration. This book is designed as a study aid and further reading may be required. Every effort has been made to identify and reference the information within this book. Any omissions or inaccuracies are not intentional and will be rectified upon notifying the publisher.
Preface
This book is designed to take some of the mystery out of the education for paramedics, a handy go‐to text for students, professionals and educators alike. The aim of this book is to provide the basis to understand the key areas of paramedic sciences and practice.
The reason for developing this book was to provide a different option away from the heavy clinical textbooks with the goal of providing succinct and easily digestible information. This should help not only with the stress of exams during the training period of being a paramedic but also throughout your career as a professional as a handy reference tool.
Paramedicine as a profession has developed in leaps and bounds since the early days of its inception. Not only are paramedics and pre‐hospital clinicians performing at a level that would seem far‐fetched only a decade or so ago but now the profession has extended beyond the realms of solely working on a 999‐response vehicle. Extended scope, specialist and advanced practice are all now very much within the grasp of paramedics. However, understanding the basics of the profession is the key to developing a core knowledge base on which to build.
Although titled for paramedics, most of the underpinning themes and knowledge cross professional boundaries with other allied health professionals and the nursing profession. I hope that this text is of use to any and all that read it.
Since the introduction of undergraduate higher education for paramedics, there has been more emphasis on the academic abilities of a paramedic, I hope that this book will help guide your revision and study throughout your training and career.
1Paramedic anatomy and physiology – 1
Contents
Anatomical and medical terms
Questions
References and Further Reading
Cellular biology
Quick Questions
References and Further Reading
The nervous system
Questions
Questions
References and Further Reading
The respiratory system
Questions
Quick Questions
References and Further Reading
The cardiovascular system
Questions
The heart
Questions
Electrocardiogram (ECG)
References and Further Reading
The gastrointestinal system
References and Further Reading
The endocrine and exocrine system
Questions
References and Further Reading
The renal and urinary system
Questions
References and Further Reading
The skeletal system
References and Further Reading
The muscular system
References and Further Reading
The integumentary system
Questions
References and Further Reading
Paediatrics
References and Further Reading
This section will take you through the basics of anatomy, physiology and some pathophysiology required for your learning. Physiology is often overlooked but it underpins every aspect of clinical care within medicine. By understanding the physiology you can interpret how the patient is presenting even if you don't know what is wrong with them, from this you will be able to form management plans to alter the physiology back to normal.
Firstly what you will need to learn is how to classify areas of the body and general terms for describing movement and positioning within healthcare. It may seem daunting at first but with repetition and application in practice the terms will stick. There are regular question breaks throughout to check your learning.
Anatomical and medical terms
Anatomy – The science of the body structures and the relationship between them studied by dissection.
Physiology – The science of how the body functions and the actions of each organ.
The anatomical position – Facing forwards with palms forwards
Regions of the body
Figure 1.1 A labeled representation presented in the anatomical position.
Directional terminology
Superior – Above or higher to the point described e.g. the head is superior to the shoulders
Inferior – Below or lower to the point described e.g. the bowel is inferior to the diaphragm
Anterior (Ventral) – Towards the front of (using the anatomical position) e.g. the sternum is anterior to the heart.
Posterior (Dorsal) – Towards the back of e.g. the oesophagus is posterior to the trachea
Medial – Closer to the midline e.g. the heart is medial to the lungs
Lateral – Further from the midline e.g. the lungs are lateral to the heart
Ipsilateral – On the same side as e.g. the gallbladder and the appendix are ipsilateral
Contralateral – On the opposite side to e.g. the spleen is contralateral to the ascending colon
Proximal – Closer to the point of origin e.g. the knee is proximal to the ankle
Distal – Further from the point of origin e.g. the wrist is distal to the elbow
Superficial – Closer to the surface e.g. the epidermis is superficial to the subcutaneous
Deep – Further below the surface e.g. the subcutaneous is deep to the epidermis
Anatomical planes
Midsagital – Divides the body or organ vertically into equal left and right portions
Parasagital – Divides the body or organ vertically into unequal left and right portions
Frontal (Cronal) – Divides the body or organ vertically into anterior and posterior portions
Transverse – Divides the body or organ horizontally into superior and inferior portions
Oblique – Passes through the body or an organ at an angle
Postural terms
Supine – Lying on their back
Prone – Lying on their front
Right lateral recumbent ‐ Lying on their right side
Left lateral recumbent ‐ Lying on their left side
Fowlers – Sitting up with legs bent or straight
Tredelenburg – Lying supine with their legs raised
These terms, although it may not seem it now, are essential to your practice as they allow for greatly improved paperwork, handovers and conversations with colleagues.
Planes of movement
Abduction – Movement away from the midline e.g. raising arms out (to abduct)
Adduction – Movement towards the midline e.g. lowering arms (to add together)
Flexion – Bending at a joint e.g. raising forearm (flexing biceps)
Extension – Straightening a joint e.g. lowering forearm (extending a hand to shake)
Medial rotation – Turning inwards e.g. toe in
Lateral rotation – Turning outwards e.g. toe out
Supination – Rotation of the forearm so that the palm faces forwards (palm UP)
Pronation – Rotation of the forearm to that the palm faces backwards (palm DOWN)
Abdominal regions
Figure 1.2 Labeled nine regions of the abdomen.
Questions
Without looking, define the following terms. (These you can check yourself)
Anterior
Proximal
Inferior
Medial
Superficial
The last few pages have been very wordy so here are some questions just to help test if it has gone in. See what you can do without looking.
Fill in the blanks
The kidneys are ______________________ to the stomach
The shoulders are ______________________ to the head
The trachea is ______________________ to the oesophagus
Brain is found in the ______________________ region
The fingers are ______________________ to the wrist
A patient found lying on their back is said to be in what position?
The plane that divides the body or an organ vertically into equal left and right portions is what?
What movement is involved when the hand touches the shoulder?
Further questions – don't worry if you can't answer these now you may choose to research these now, but if not be sure to revisit them later.
The appendix is found in which region? (Try to use the nine segments)
Trendelenburg position is primarily utilised in patients with what?
Shortening and lateral rotation of a leg is a sign of (but not definitively) what?
Answers can be found at the back of the book
References and Further Reading
Gregory, P. and Ward, A. (2010).
Sanders’ Paramedic Textbook
. Edinburgh: Mosby Elsevier.
Marcovitch, H. (2017).
Black’s Medical Dictionary
, 43e. London: Bloomsbury.
Tortora, G.J. and Derrickson, B.H. (2017).
Tortora’s Principles of Anatomy and Physiology
, 15e. Chichester: Wiley.
Waugh, A. and Grant, A. (2018).
Ross and Wilson Anatomy and Physiology
. Edinburgh: Elsevier.
Cellular biology
Nice to know or need to know? This may seem a bit in depth for a Paramedic however having a good understanding at this level allows for a greater understanding on a larger scale. The benefits will also show when discussing drugs later on! Let’s start with the basics.
Cells are complicated but the basics can be broken down at this level. We will build on this throughout the book so it's worth getting an understanding now. So what makes up a cell?
Parts of a cell
Figure 1.3 Labeled diagram of a cell.
The cell wall
Figure 1.4 Simplified depiction of the phospholipid bilayer of a cell wall.
Functions of the main organelles
Nucleus – Storage and synthesis of DNA
Mitochondria – Production of energy in the form of ATP (Adenosine triphosphate) by respiration
Rough Endoplasmic Reticulum – Protein synthesis
Smooth Endoplasmic Reticulum – Lipid synthesis
Centrioles – Microtubules associated with nuclear division
Golgi apparatus – Storage, modification and packaging of proteins and other chemicals
Biological terms
Diffusion – The movement of substances from an area of high concentration to low concentration.
Facilitated diffusion – The movement of substances from an area of high concentration to low concentration using a carrier protein or protein channel.
Osmosis – The movement of water from an area of high concentration to low concentration through a semi‐permeable membrane. (Only refers to water).
Active transport – The movement of substances against the concentration gradient using energy (i.e. area of low concentration to an area of high concentration).
Tissue
Tissues can be classified into four main groups.
Epithelial e.g. skin
Connective tissue e.g. ligaments
Muscle e.g. bicep
Nervous e.g. neurons
However epithelial tissue is further divided into:
Squamous – Thin and flat
Cuboidal – Cube shaped
Columnar – Column structure
Simple – Single layer
Stratified – Multi‐layered cells
Ciliated – Possess cilia (the so‐called ‘hairy’ cells)
So why is this important? Well understanding what the organelles do allows you to work out what may be affected if they stop functioning correctly. Classification of cells is especially important as it allows you to gain a better knowledge of how larger areas work, for example the Mucociliary escalator in the trachea.
Quick Questions
Cover up the previous information and answer the following statements with true or false.
The smooth endoplasmic reticulum synthesises protein.
The blood is an example of connective tissue.
Diffusion is the movement of water from an area of
high
concentration to
low
concentration.
Human cells contain a cell wall.
The tail of the cells in the phospholipids bilayer is hydrophilic.
References and Further Reading
Alberts, B., Johnson, A., Lewis, J. et al. (2015).
Molecular Biology of the Cell
, 6e. Abingdon: Garland Science.
Gregory, P. and Ward, A. (2010).
Sanders’ Paramedic Textbook
. Edinburgh: Mosby Elsevier.
Tortora, G.J. and Derrickson, B.H. (2017).
Tortora’s Principles of Anatomy and Physiology
, 15e. Chichester: Wiley.
Waugh, A. and Grant, A. (2018).
Ross and Wilson Anatomy and Physiology
. Edinburgh: Elsevier.
The nervous system
The nervous system is often a complex part of the anatomy to discuss at it has many different aspects and its functions are widespread. This section will try to break it down into easy to digest sections.
Feedback systems
The nervous system uses feedback systems in order to maintain homeostasis. Homeostasis is defined as equilibrium in the body's internal environment. This is done by constant interaction from the body's many regulatory processes.
Feedback systems have three sections
Sensory
Control centre
Effectors
Negative feedback systems reverse a change in a controlled condition e.g. the body's internal temperature. When the temperature is too high the body dilates peripheral circulation and increases sweating amongst other methods.
Positive feedback systems strengthen or reinforce a change in a controlled condition for a better outcome e.g. labour. When there is pressure applied to the cervix by the foetus during labour the body releases oxytosin which induces cervical dilation. This increases until the pressure is relieved by the baby being born.
The major functions of the nervous system are to:
Send and receive
sensory
functions
Send and receive
motor
functions
Integrate information
Storage of information
Analysis of information
Decision making
The nervous system can be divided into its major sections as follows.
Brain
Brain stem
Cranial nerves
Spinal cord
Central nervous system
Peripheral nervous system
The brain has four lobes:
Frontal
Parietal
Temporal
Occiptal
The brain also encompasses the cerebellum and brainstem
Figure 1.5 Labeled diagram depicting the regions of the brain.
Neuronal anatomy
The central nervous system refers to the brain and spinal cord. It integrates information from the peripheral nervous system. The peripheral system consists of everything outside of the brain and spinal cord.
Nervous tissue consists of two main types
Neuroglia
Neurones
Neuroglia assists the nervous system in maintaining homeostasis
Table 1.1 Denoting the difference in neuroglia between the central and peripheral nervous system.
Neuroglia in the central nervous system
Neuroglia in the peripheral nervous system
Astrocytes
Metabolise neurotransmitters
Assist impulse transmission
Form the blood–brain barrier
Satellite cells
Support neurones in ganglia
Oligodendrocytes
Form myelination
Schwann cells
Form myelination
Microglia
Phagocytic cells
Ependymal cells
Ciliated for assisting movement of Cerebrospinal fluid
Neurons carry the impulses to and from the brain and have three main types
Unipolar
Bipolar
Multipolar
Figure 1.6 Simplified depiction of neurons.
Definitions
Stimulus – Change in the environment (internal or external) that is strong enough to create an action potential.
Action potential – The ability to respond to stimuli with an electrical impulse.
Threshold – A point that when reached or surpassed by a stimulus releases an action potential.
Afferent – sensory, carries an action potential towards the central nervous system.
Efferent – motor, carries an action potential away from the central nervous system.
Remember S.A.M.E. Sensory is Afferent, Motor is Efferent
Myelination
Electrical insulation of the neuron
Increases speed of impulse conduction
Conduction of impulses
Continuous
Non
‐myelinated neurones.
Domino effect. As sodium flows in during depolarisation the neighbouring gates open.
Refractory period prevents the conduction from travelling backwards.
Saltatory
Occurs in myelinated neurones.
Impulse ‘jumps’ between Nodes of Ranvier.
Allows for faster conduction.
Resting cell membrane potential and conduction in the average neuron
Rests at −70 mV.
Depolarises to +30 mV.
Returns to resting.
Why do you need to know this? At this level, it may seem a bit much but at level two you are able to administer drugs that affect this process so having a good understanding now makes it easier.
Action potential response to stimulus
Figure 1.7 Diagram demonstrating the electrical response (action potential) to a stimulus.
Conduction
Figure 1.8 Visual representation of propagation of an impulse along a cell membrane.
Speed of impulse propagation
The speed of propagation is dependent on the strength of the impulse.
Factors that increase the speed of propagation are:
Larger diameter fibres
Myelination
Warmer temperatures
Synapses
Electrical
Found in the heart
Current spreads through
gap junctions
Allows for synchronised conduction to achieve co‐ordinated contraction
Two way unlike a chemical synapse, this helps explain how an impulse can travel ‘backwards’ in the heart.
Chemical
Occur where two neurones meet
The gap between them is bridged by neurotransmitters
A neurotransmitter is released when an action potential reaches the axon bulb forcing the chemicals to be released into the synapse by exocytosis.
Neurotransmitter is received by a receptor on the postsynaptic bulb
Here, an action potential can be stimulated or blocked
One‐way impulse conduction
Neurotransmitters
Work to open or close specific ion channels
Some work slowly by secondary messenger systems
Result in excitation or inhibition of postsynaptic neuron
Many are hormones secreted by endocrine organs
This bit is probably in the nice to know section at this stage but definitely worth a read
Examples of neurotransmitters
Acetylcholine – used in the Parasympathetic nervous system (this will be covered later) can be affected by organophosphate overdoses
Epinephrine – Adrenaline used for fight or flight responses
Dopamine – creates feeling of elation. This can be affected by illicit drugs such as cocaine
Gamma Aminobutyric Acid (GABA) – affected by diazepam
Serotonin – patients may be on Selective Serotonin Reuptake Inhibitors (SSRI's)
Enkephalins and Endorphins – Released by exercise, chocolate etc.
Questions
Fill in the blanks
Myelinated neurones use _________________ conduction
Feedback systems require the following functions; sensory, _________________ and _________________.
An _________________ neuron carries impulses away from the Central Nervous System
We're not done on the nervous system yet, but here are some questions to test what you know so far
Answer the next statements with True or False
Temperature control is an example of positive feedback
The axon contains the cell nucleus
An action potential is the ability to respond to a stimuli with an electrical impulse
Chemical synapses are two way
What forms the myelin sheath in the Central Nervous System?
What factor can be utilised by a paramedic to increase the effectiveness of analgesia?
The cerebrum
Is the most superior part of the brain and consists of two main areas
Cortex, which is the outer layer consisting of grey matter (Non‐mylenated)
Medulla, which is the inner layer consisting of white matter (Mylenated)
The cerebrum is divided into left and right hemispheres by the Falx Cerebri which is an extension of the Dura Mater.
The three principal functions are
Mental activity
Sensory perception
Control of voluntary muscle
The Cerebrum contains basal ganglia that are groups of neurones that assist in the control of large automatic movements. These are affected in patients suffering from Parkinson's.
The limbic system is located in the Cerebrum and Diencephalon and controls the emotional aspects of behaviour related to survival. It also plays a role in memory.
There are ventricles in the brain containing cerebral spinal fluid.
Lateral – One in each cerebral hemisphere
Third – Between and inferior to the left and right hemisphere
Fourth – Between the brain stem and cerebellum
The cerebellum
Controls the skeletal muscle contractions required for
Balance
Posture
Skilled movements
Muscle tone
Compares the intended movement with the actual movement
Diencephalon
Thalamus
80% of the diencephalon
Relays all sensory information to cerebral cortex
Crude appreciation of senses; e.g. pain, heat so that it can be directed to appropriate areas of the brain
Hypothalamus
Controls and integrates with the Autonomic Nervous system
Associated with rage and aggression
Regulates
Body temperature
Fluid intake via thirst centre
Food intake via feeding and satiety centres
Waking and sleeping patterns associated with the reticular activating system
Connects nervous system and endocrine systems
The brain stem
Midbrain
Approximately 2.5 cm in length (In the average adult)
Connects the Pons to the Diencephalon
Carries Motor impulses to and from the spinal cord to cerebrum and cerebellum
Directs impulses
Origin of Cranial Nerves III and IV
Pons Varolii
Approximately 2.5 cm in length (In the average adult)
Connects spinal cord to the brain
Links various areas of the brain
Pneumotaxic area
Shortens inspiratory phase to increase respiration rate
Apneustic area
Lengthens expiratory phase to decrease respiration rate
Origin on Cranial Nerves V–VII
These are important to know as it allows you to work out how a patient may present if one of these areas is affected e.g. a brain stem CVA.
Medulla Oblongata
Approximately 2.5 cm in length (In the average adult)
Contains the Pyramids of Decussation which cross the neuron paths
Contains the following
Cardiac centre ‐ control of the cardiac muscle
Respiratory centre ‐ control aspects of breathing
Vasomotor centre – control of vascular tone e.g. vasoconstriction
Possesses reflex centres for; coughing, sneezing, hiccupping, swallowing, vomiting, etc.
Origin of Cranial Nerves VIII–XII
Cranial nerve X is the Vagal nerve
Spinal cord
The Spinal cord has three protective coverings called meninges, these also extend over the brain. These are called the Dura mater, Arachnoid mater and the Pia mater. The spinal cord terminates at the superior border of L2 where it becomes the Cauda Equina.
Dura mater
Outermost covering made of dense connective tissue
Stops expansion of brain and spinal cord
Arachnoid mater
Middle layer made from a web of collagen fibres
Avascular (without blood, oxygen and nutrients are provided by the Cerebrospinal fluid)
CSF circulates in Sub‐Arachnoid space
Pia mater
Innermost layer made from thin transparent connective tissue
Contains blood vessels
In the spinal cord, white mater surrounds the grey mater centre, the opposite of the brain.
Figure 1.9 Visual representation of the layers of the spinal cord.
Spinal cord functions
Anterior portion controls motor nerves
Posterior portion controls sensory nerves
Links brain to the peripheries
Relays messages entering and leaving at the same level
Relays messages entering and leaving at different levels
Relays messages to and from the brain
Acts as centre for reflex action
Reflex arc
Figure 1.10 Simplified diagram of a spinal reflex arc.
Cortical reflex
Follows the spinal reflex to
Reinforce, modify or inhibit reaction
Apply the appropriate response e.g. swearing
Autonomic reflex
No conscious control e.g. rises in blood pressure resulting in vasodilatation etc.
Can occur independently or in conjunction with other systems to maintain homeostasis
Important nerves
The
Phrenic
nerve leaves the spinal cord at C3–5
The
Cardiac
nerves leave the spinal cord at T1–4
The
Intercostal
nerves leave the spinal cord at T2–12
Remember the phrase ‘Three, four and five keeps you alive’ and you will never forget the phrenic nerve!
Cerebrospinal fluid (CSF)
The CSF is formed in the ventricles of the brain by filtration of the blood plasma, a process done by the Choriod Plexuses. An average adult has approximately 80–150 mL of circulating fluid which is re‐absorbed at a rate of 20 mL/hour by the arachnoid villi and venous dural sinuses.
Its main functions are
Mechanical protection
Cushions tissues from being damaged by cranial and vertebral bones
Chemical protection
Optimal environment for hormonal activity
Changes in the CSF can affect neurotransmitters
Circulation
Medium for the exchange of nutrients and waste substances
Peripheral nervous system
Figure 1.11 Diagram denoting the facets of the peripheral nervous system.
Somatic nervous system
From the muscle to the CNS
Sensory neurones and proprioceptors
Proprioceptors detect movement to allow brain to estimate where the limb is in relation to the body in addition to rigorous, e.g. exercise, movement stimulating the respiratory centre to keep up with an increased oxygen demand.
Enteric nervous system
‘Brain of the gut’
Controlled by Enteric Plexuses
Work, to an extent, separate from the Central and Autonomic Nervous systems
Communicate with the CNS by parasympathetic neurones
Monitor changes e.g. Chemical levels in the Gastrointestinal tract
Autonomic nervous system
Network of sensory neurons all over the body
No conscious control
Maintains homeostasis
Controls; blood pressure, blood flow, body temperature, digestion, respiration, etc.
Sub‐divided into the Sympathetic and Parasympathetic nervous systems
Sympathetic nervous system
Known as the ‘
accelerator
’
Expends energy
Mainly uses Epinephrine and Norepinephrine as neurotransmitters
Leaves from the spinal cord
Parasympathetic nervous system
Known as the ‘
brake
’
Conserves energy
Mainly uses Acetylcholine as a neurotransmitter
Leaves from the brainstem and sacrum
Effects of the autonomic nervous system
Ciliary muscle
Ring of smooth muscle holding the lens in the eye
Receives only
Parasympathetic
innervations
Acetylcholine (ACh) causes constriction to allow for near vision
Iris
Receives both
Sympathetic
and
Parasympathetic
innervations
Parasympathetic
causes pupil to constrict (Miosis)
Sympathetic
causes pupil to dilate (Mydriasis)
Heart
Receives both
Sympathetic
and
Parasympathetic
innervations
Parasympathetic
innervates the Sinoatrial node to induce bradycardia
Parasympathetic
nervous system does
not
innervate the myocardium
Sympathetic
innervates all regions of the heart
Increases rate at Atrioventricular node
Increases conduction through the purkinjee fibres
Increases force of ventricular contraction
A young healthy heart is dominated by Vagal tone
Respiratory
Receives both
Sympathetic
and
Parasympathetic
innervations
Parasympathetic
evokes constriction of smooth muscle leading to bronchoconstriction
Sympathetic
evokes dilation of smooth muscle leading to bronchodilation
Gastrointestinal
Receives both
Sympathetic
and
Parasympathetic
innervations
Normally dominated by parasympathetic tone
Parasympathetic
nervous system causes increased gut motility
Sympathetic
causes a reduction in cut motility
Urinary Bladder
The Detruser muscle is controlled by the parasympathetic
The Trigone muscle is controlled by the sympathetic
It is important to understand the role of the autonomic nervous system, as it will help you understand more about the physiology of a patient's condition. It will also help you when we move on to talk about drugs you might give later on.
Think of the Autonomic Nervous system in terms of the fight or flight response. For example, you are walking home alone at night and you decide to take the shortcut down a dark alley. In the alley, you are confronted by a mad axe man who states he is going to kill you (doesn't seem like such a good idea anymore does it?). The Sympathetic or ‘Accelerator’ kicks in which results in:
Pupil dilation as you want to be able to see where you are going so you don't trip over
Increased heart rate as you want the blood circulating faster so you can run away
Arties dilate improving blood supply to skeletal muscle so that you can run faster
Bronchi dilate as you need to breathe easily to continue running
GI tract decreases in motility as you don't want to defecate yourself (that would just be embarrassing)
Bladder, well that works roughly in the same sense as the GI tract.
Table 1.2 Effects of nervous system innervation on the sympathetic and parasympathetic nervous system.
Effect of nervous innervations on
Sympathetic
Parasympathetic
Eye
Dilation of pupils and relaxation of lens for enhanced vision
Constriction of pupils and contraction of lens for near vision
Heart
Increased heart rate, contractility and conduction velocity
Decreased heart rate, contractility and conduction velocity
Arterial system
Constrict most blood vessels, dilates vessels to; heart, lungs and skeletal muscle
Supply very few vessels for vasodilatation
Bronchi
Relaxes bronchial smooth muscle and inhibits the secretion of mucus
Contracts bronchial smooth muscle and stimulates the secretion of mucus
Stomach
Decreases the motility and keeps the sphincters closed
Increases the motility and opens the sphincters
Bladder
Relaxes bladder wall and contracts the sphincter
Contracts the bladder wall and relaxes the sphincter
Questions
Fill in the blanks
The cortex is the _________________ layer of the cerebrum
The most superior part of the brainstem is the _________________
Directly inferior to that is the _________________
The most inferior part of the brainstem is the _________________
The _________________ nerve leaves at level C3‐5
The _________________ nervous system is known as the ‘brain of the gut’
Answer the statements with True or False
The cerebrum contains the reflex centres for vomiting and coughing
The hypothalamus is the largest part of the diencephalon
The vagus nerve originates in the medulla oblongata
Sympathetic stimulation with case a decrease in the motility of the stomach and the opening of the sphincters
Where are the Pyramids of Decussation found?
Name the three meninges of the brain and spinal cord.
How much circulating Cerebrospinal fluid does the average adult have?
References and Further Reading
Alberts, B., Johnson, A., Lewis, J. et al. (2015).
Molecular Biology of the Cell
, 6e. Abingdon: Garland Science.
Crossman, A.R. and Neary, D. (2019).
Neuroanatomy
, 6e. London: Elsevier.
Gregory, P. and Ward, A. (2010).
Sanders’ Paramedic Textbook
. Edinburgh: Mosby Elsevier.
Lou, L. (2015).
Principles of Neurobiology
. London: Taylor and Francis Group.
Tortora, G.J. and Derrickson, B.H. (2017).
Tortora’s Principles of Anatomy and Physiology
, 15e. Chichester: Wiley.
Waugh, A. and Grant, A. (2018).
Ross and Wilson Anatomy and Physiology
. Edinburgh: Elsevier.
The respiratory system
Respiratory complaints are a common presentation to the ambulance service, therefore, understanding the basic anatomy and physiology will help with your understanding of the disease process. This section will not look at illnesses in detail as this will be covered later.
Components
Nose
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Terminal Bronchioles
Alveolar Ducts
Alveoli
Lungs
Nose
External
Bone and Hyaline cartilage covered by muscle and skin
Two openings (Nares) separated by the septum
Lined with mucous and hairs
Internal
Large cavity in skull
Inferior to cranium, superior to mouth
Merges the external nares to the pharynx
Lateral walls make from; Ethmoid, Maxillae, Lacrimal, Palatine and inferior Conchae bones
Roof formed if Palatine bones
Contains three ‘shelves’ formed by projection of nasal chonchae
Highly vascular
These two are probably a nice to know but still useful
Functions
Warm air
Moisten air
Filter air
Receive olfactory stimulus
Resonating chamber for speech sounds
Pharynx
Funnel‐shaped tube approximately 13 cm long in the average adult
Extends from the internal nares to the cricoids cartilage
Skeletal muscle with mucous membrane
Supplied by cranial nerves IX, X, and XI
Separated into three parts the Nasopharynx, Oropharynx and the Laryngopharynx
Nasopharynx
Extend from nares to level of soft palate
Five openings
Two external nares
Two Eustachian tubes
One opening to Oropharynx
Pharangeal tonsil on posterior wall (adenoid)
Functions
Receive air from internal nares
Equalise pressure in the ears, nose and throat
Filters dust‐laden particles
Oropharynx
Extends from soft palate to level of hyoid bone
Lined with stratified squamous epithelium
Contains Palatine and Lingual Tonsils
Figure 1.12 Labeled diagram of the upper airway.
Laryngopharynx
Most inferior portion of pharynx
Opens into
Oesophagus (posterior)
Larynx (anterior)
Lined with stratified squamous epithelium
Larynx
Contains nine pieces of cartilage
Single cartilage
Thyroid
Epiglotis
Cricoids
Paired cartilageis
Arytenoids
Corniculate
Cuneiform
Glott
At this level understanding, the Larynx contains nine pieces of cartilage should be sufficient. However, it will help in a later section where these will be studied in greater detail. It will also be covered when discussing Endotracheal Intubation.
Trachea
Approximately
12 cm in length in the average adult
Approximately
2.5 cm in diameter in the average adult
16–20 ‘C’ shaped cartilages incomplete posterior to allow food passage down the oesophagus
Lined with pseudo stratified ciliated columnar epithelium
Mucociliary Escalator ‘wafts’ Mucous towards pharynx for expulsion
Don't get too concerned with the measurements, as everyone is individual.
Bronchi
Bifurcate from the Trachea at the Carina at the level of T5
The right main bronchus is shorter, wider and more vertical than the left
Composed of incomplete rings of hyaline cartilage and pseudo stratifies ciliated columnar epithelium
On entry to the lungs at the Hilum they split into the secondary bronchi
These then divide into tertiary bronchi
These then divide into the bronchioles
Cartilage is gradually replaced by smooth muscle in the bronchioles
Bronchioles
Are to respiration what arterioles are to circulation
Varying the diameter controls the air movement
Divide into terminal bronchioles
Alveoli
Approximately 150 million in the average adult
Allow gas exchange between the blood and air
Use natural surfactants to stop them from collapsing and sticking
Increase surface area in the lungs
Lungs
Right lung has three lobes
Left lung has two lobes due to the cardiac notch
Surrounded by the pleura which has two layers
Visceral pleura attaches to the lung to allow smooth expansion
Parietal pleura anchors the lungs to the chest wall
Space in‐between in known as the pleural cavity
Can become infected and cause pleuritis or pleurisy
Fluid entering the pleural cavity is known as
pleural effusion
Knowing the definition of these terms and the volumes is important in aiding your understanding of the patient's conditions. Also, it will help guide your treatment if you understand the physiological processes going on.
Figure 1.13 Labeled diagram of the respiratory tract.
Respiratory processes
Pulmonary Ventilation
Mechanical flow of air in and out of the lungs
External Respiration
Exchange of gasses from the alveoli to the blood and back again
Internal Respiration
Exchange of gasses between blood and tissues
Pulmonary volumes
Tidal volume
Normal air inhaled and exhaled during normal breathing
Approximately 500 mL in the average adult
Inspiratory reserve volume
Largest additional volume that can be forcibly inhaled above tidal
Approximately 3100 mL in the average adult
Expiratory reserve volume
Largest additional volume that can be forcibly exhaled above tidal
Approximately 1200 mL in the average adult
Residual volume
Amount of air that cannot be forcibly exhaled from the lungs
Approximately 1200 mL in the average adult
Vital capacity
Largest volume of air that can be inhaled and exhaled from the lungs in one go
Approximately 4800 mL in the average adult
Dead air space
Amount of air left in conducting airways
Approximately 150 mL in the average adult
Figure 1.14 Example spirograph annotated.
Total lung capacity
Amount of air that can be held in the lungs
Approximately 6000 mL in the average adult
Breathing
Breathing is the movement of air in and out of the lungs. This is done by creating a pressure gradient by the movement of the diaphragm and the ribs. On inhalation, the pressure in the lungs is lower than atmospheric air so air moves into the lungs. On exhalation, the pressure in the lungs is greater than atmospheric air so the air is drawn out again.
The relevance of this is that naturally we breathe by negative pressure; however, when you are ventilating your patient you will use positive pressure. What effect might this have? What about if they have a pneumothorax?
Figure 1.15 Pressure changes during inhalation and exhalation.
Exchange
This takes place due to pressure gradients within the body. These are created by differing Partial pressures (p) of gasses.
Figure 1.16 Gas exchange within the alveoli.
Questions
Fill in the blanks
The Pharynx is supplied by cranial nerves _________________, _________________ and _________________.
The trachea bifurcates at the _________________.
The average expiratory reserve volume is _________________.
Normal breathing requires _________________ pressure.
Answer the following statements with True of False
The nose has external and internal sections
The trachea contains 16–20 ‘C’ shaped cartilages incomplete anterior to allow food passage down the oesophagus
The right lung has three lobes
Why is the right main bronchus more prone to blockage?
Define external respiration.
Regulation
Breathing is regulated by nervous control and chemical regulation.
Nervous control is regulated by the respiratory centres in the brainstem.
Chemical regulation is controlled by the chemoreceptors.
When there is a rise in pCO
2
in the blood it stimulates the brainstem to induce breathing.
In patients with advanced Chronic Obstructive Pulmonary Disease (COPD) the body’s chemoreceptors can become accustomed to a higher level of CO2 in the blood and, therefore, less responsive. As a result, in a small cohort of patients, breathing will be stimulated by a reduction the in concentration of oxygen in the blood. This can be referred to as the Hypoxic Drive.
