Cover
Title Page
Copyright Page
Preface
Abbreviations
Acknowledgements
How to use your revision guide and the companion website
1. Features contained within your revision guide
Part 1: Foundations
1. 1 Anatomical terms
  1. Anatomical position
  2. Anatomical terms
  3. Directional terms
  4. Planes
  5. Body cavities
2. 2 Genetics and genomics
  1. DNA and RNA
  2. Mitosis, meiosis and fertilisation
  3. Mitosis
  4. Meiosis
  5. Fertilisation
3. 3 Homeostasis
  1. Homeostasis
  2. Feedback mechanisms
  3. Negative feedback
  4. Positive feedback
4. 4 Fluid compartments
  1. Body water
  2. Location of body fluids
  3. Maintaining fluid balance
  4. Body fluid movement
5. 5 Cells and organelles
  1. Components of a cell
6. 6 Transport systems
  1. Simple diffusion
  2. Facilitated diffusion
  3. Osmosis
  4. Endocytosis and exocytosis
7. 7 Blood
  1. Functions
  2. Blood components
  3. Development of blood cells
8. 8 Inflammation and immunity
  1. Immunity
  2. Inflammation
9. 9 Tissues
  1. Epithelial tissue
  2. Nervous tissue
  3. Connective tissue
  4. Muscle tissue
Part 2: The nervous system
1. 10 The brain and nerves
  1. The brain
  2. The meninges
  3. The cerebrospinal fluid
  4. The neuron
  5. Cranial nerves
2. 11 The structures of the brain
  1. Cerebrum
  2. Diencephalon
  3. Brainstem
  4. Cerebellum
  5. Limbic system
  6. Ventricles of the brain
  7. Cerebrospinal fluid
3. 12 The spinal cord
  1. Spinal cord sections
  2. Functions of the spinal cord
  3. Reflex actions
  4. Spinal nerves
4. 13 The blood supply
  1. Circle of Willis
  2. The blood–brain barrier
5. 14 The autonomic nervous system
  1. Sympathetic nervous system
  2. Parasympathetic nervous system
  3. Autonomic control by the CNS
  4. Autonomic reflexes
6. 15 The peripheral nervous system
  1. Peripheral nervous system connections
  2. Sensory division
  3. Motor division
Part 3: The heart and vascular system
1. 16 The heart
  1. Walls of the heart
  2. Chambers of the heart
  3. Valves of the heart
  4. Blood vessels of the heart
2. 17 Blood flow through the heart
  1. Blood flow
  2. Pulmonary circulation
  3. Systemic circulation
  4. Coronary circulation
  5. Coronary arteries
  6. Coronary veins
3. 18 The conducting system
  1. Cardiac conduction
  2. Sinoatrial node
  3. Atrioventricular node
  4. Bundle of His
  5. Left and right bundle branches
  6. Purkinje fibres
  7. The cardiac cycle
4. 19 Nerve supply to the heart
  1. The autonomic nervous system
  2. Chemical regulation
  3. Baroreceptors
  4. Other factors in heart regulation
5. 20 The structure of the blood vessels
  1. The blood vessels
  2. Structure of the blood vessels
  3. The arteries
  4. The veins
  5. The capillaries
6. 21 The blood pressure
  1. What is blood pressure?
  2. Physiological factors
  3. The control of blood pressure
  4. Taking a blood pressure measurement
7. 22 The lymphatic circulation
  1. Functions of the lymphatic system
  2. The lymphatic system
  3. Lymph
  4. Lymph nodes
  5. Lymphatic organs
Part 4: The respiratory system
1. 23 The respiratory tract
  1. Upper respiratory tract
  2. Lower respiratory tract
  3. Blood supply
2. 24 Pulmonary ventilation
  1. Breathing
  2. Inspiration
  3. Exhalation
  4. Factors affecting pulmonary ventilation
  5. Lung volumes
3. 25 Control of breathing
  1. Medullary rhythmic area
  2. Pneumotaxic area
  3. Apneustic area
  4. Central chemoreceptors
  5. Peripheral chemoreceptors
  6. Inflation reflex
  7. Other influences on respiration
4. 26 Gas exchange
  1. External respiration
  2. Exchange of gases in the lungs
  3. Fick’s Law
  4. Internal respiration
  5. Factors affecting pulmonary and systemic gas exchange
  6. Transport of gases
Part 5: The gastrointestinal tract
1. 27 The upper gastrointestinal tract
  1. The mouth (the oral cavity)
  2. Oesophagus
  3. Stomach
2. 28 The lower gastrointestinal tract
  1. The small intestine
  2. The large intestine (the colon)
3. 29 The liver, gall bladder and biliary tree
  1. The liver
  2. The gall bladder
4. 30 The pancreas and spleen
  1. The pancreas
  2. The spleen
5. 31 Digestion
  1. Mechanical digestion
  2. Chemical digestion
  3. Digestion and absorption
Part 6: The urinary system
1. 32 The kidney (microscopic)
  1. Nephrons
  2. Bowman’s capsule
  3. Glomerulus
  4. Proximal convoluted tubule
  5. Loop of Henle
  6. Distal convoluted tubule
  7. Collecting ducts
2. 33 The kidney (macroscopic)
  1. The kidney
  2. Renal cortex
  3. Renal medulla
  4. Renal pelvis
  5. Blood supply
  6. Nerve supply
3. 34 The ureters, bladder and urethra
  1. The ureters
  2. The urinary bladder
  3. The urethra
4. 35 The formation of urine
  1. Filtration
  2. Selective reabsorption
  3. Secretion
  4. Hormonal control
  5. Aldosterone
Part 7: The male reproductive system
1. 36 The external male genitalia
  1. The testes
  2. Spermatogenesis
  3. The penis
  4. The epididymis
  5. Vas deferens, ejaculatory ducts and spermatic cord
2. 37 The prostate gland
  1. Zones of the prostate gland
  2. Surfaces of the prostate gland
  3. Function of the prostate gland
  4. Some structures around the prostate gland
  5. Prostate specific antigen
3. 38 Spermatogenesis
  1. Male sex hormones
Part 8: The female reproductive system
1. 39 The female internal reproductive organs
  1. Internal female reproductive organs
  2. Female sex hormones
  3. The uterus
  4. The fallopian tubes
  5. The vagina
  6. The cervix
2. 40 The external female genitalia
  1. Mons veneris
  2. Labia majora
  3. Labia minora
  4. Clitoris
  5. Urethra
  6. Hymen
  7. Blood supply
  8. Lymphatic drainage
  9. Nerve supply
3. 41 The female breast
  1. The female breast
  2. Breast development
  3. Hormones and the breast
4. 42 The menstrual cycle
  1. The reproductive cycle
  2. The pituitary gland
  3. The follicular phase
  4. The ovulatory phase
  5. The luteal phase
  6. The menstrual cycle
Part 9: The endocrine system
1. 43 The endocrine system
  1. The endocrine glands
  2. The pituitary gland and the hypothalamus
  3. The pineal gland
  4. The anterior pituitary lobe
  5. The posterior pituitary lobe
2. 44 The thyroid and adrenal glands
  1. The thyroid gland
  2. Parathyroid glands
  3. The adrenal glands
3. 45 The pancreas and gonads
  1. The pancreas
  2. The gonads
  3. Other endocrine glands
Part 10: The musculoskeletal system
1. 46 Bone structure
  1. Bone
  2. Ossification
  3. The skeleton
2. 47 Bone types
  1. The skeleton
  2. Skeletal divisions
  3. Bone types
3. 48 Joints
  1. Joints
  2. Movements
  3. Fibrous joints
  4. Cartilaginous joints
  5. Synovial joints
  6. Fixed joints
4. 49 Muscles
  1. Muscle tissue
  2. Properties of muscle tissue
Part 11: The skin
1. 50 The skin
  1. The layers of the skin
2. 51 The skin appendages
  1. The dermal appendages
3. 52 Epithelialisation
  1. Wounds
  2. How wounds heal
  3. Types of wound healing
  4. Wound closure
4. 53 Granulation
  1. Granulation tissue
  2. Tissue repair
  3. Overgranulation
Part 12: The senses
1. 54 Sight
  1. Vision
  2. The orbit
  3. Eyelids, lashes, eyebrows
  4. The lacrimal apparatus
  5. The sclera
  6. The cornea
  7. The aqueous humour
  8. The iris
  9. The lens and ciliary muscle
  10. The retina
  11. Visual system pathways to the brain
  12. The visual cortex
2. 55 Hearing
  1. The ear
  2. The outer (external) ear
  3. The middle ear
  4. The inner ear
3. 56 Olfaction
  1. Physiology of olfaction
  2. Olfactory nerve and cribriform plate
  3. Olfactory bulb
  4. Olfactory tract
4. 57 Gustation
  1. The tongue
  2. Anatomy and physiology
  3. Taste bud anatomy
Appendix 1: Normal physiological values
1. Full blood count
2. Coagulation
3. Haematinics
4. Biochemistry
5. Endocrinology
6. Other biochemistry tests
7. Tumour markers
8. Immunology
9. Lumbar puncture results
Appendix 2: Prefixes and suffixes
Appendix 3: Glossary
Further reading
Index
End User License Agreement

List of Tables

Chapter 1
1. Table 1.1 The body cavities.
Chapter 2
1. Table 2.1 Types of RNA.
Chapter 5
1. Table 5.1 Common elements in the body.
Chapter 8
1. Table 8.1 Types of antibodies.
Chapter 39
1. Table 39.1 The layers of the uterus.
Chapter 43
1. Table 43.1 Hormones released by the hypothalamus and anterior pituitary gla...
Chapter 44
1. Table 44.1 Some effects associated with abnormal secretion of thyroid hormo...
Chapter 45
1. Table 45.1 Other endocrine glands.
Chapter 54
1. Table 54.1 Structures of the eye.

List of Illustrations

Chapter 1
1. Figure 1.1 The standard anatomical position.
2. Figure 1.2 Anatomical terms.
3. Figure 1.3 Anatomical planes.
4. Figure 1.4 Body cavities.
Chapter 2
1. Figure 2.1 DNA and RNA.
2. Figure 2.2 Mitosis.
3. Figure 2.3 Meiosis.
4. Figure 2.4 Fertilisation.
Chapter 3
1. Figure 3.1 Components of a negative feedback system.
2. Figure 3.2 Negative feedback – raised blood pressure.
3. Figure 3.3 Negative feedback – raised temperature.
4. Figure 3.4 Positive feedback of childbirth.
Chapter 4
1. Figure 4.1 Body water content.
2. Figure 4.2 Fluid compartments.
Chapter 5
1. Figure 5.1 Structures located within body cells.
2. Figure 5.2 Mitochondrion.
3. Figure 5.3 The fluid mosaic arrangement.
Chapter 6
1. Figure 6.1 Simple diffusion.
2. Figure 6.2 Channel‐mediated facilitated diffusion of potassium ions (K+) thr...
3. Figure 6.3 Osmosis. Water molecules move through the selectively permeable m...
4. Figure 6.4 Tonicity and the red blood cell.
Chapter 7
1. Figure 7.1 Centrifuged blood.
2. Figure 7.2 Three principal formed components: red blood cells, white blood c...
3. Figure 7.3 Compoments of blood.
4. Figure 7.4 Haemopoiesis.
Chapter 8
1. Figure 8.1 Types of acquired immunity.
2. Figure 8.2 The cells of the immune system.
Chapter 9
1. Figure 9.1 Levels of organisation.
2. Figure 9.2 Types of cells.
3. Figure 9.3 Human body tissues.
Chapter 10
1. Figure 10.1 The brain.
2. Figure 10.2 The meninges.
3. Figure 10.3 The neuron.
4. Figure 10.4 The cranial nerves.
Chapter 11
1. Figure 11.1 The cerebrum.
2. Figure 11.2 The cerebellum.
3. Figure 11.3 The limbic system.
Chapter 12
1. Figure 12.1 Spinal cord and spinal nerves.
2. Figure 12.2 The meninges.
Chapter 13
1. Figure 13.1 The circle of Willis.
2. Figure 13.2 The blood–brain barrier.
Chapter 14
1. Figure 14.1 The sympathetic and parasympathetic nervous systems.
Chapter 15
1. Figure 15.1 The somatic nervous system.
2. Figure 15.2 The motor pathway.
Chapter 16
1. Figure 16.1 The location of the heart.
2. Figure 16.2 The walls of the heart.
3. Figure 16.3 Cells of the myocardium.
4. Figure 16.4 Myocardial cells.
Chapter 17
1. Figure 17.1 Blood flow through the heart.
2. Figure 17.2 The blood vessels of the heart.
3. Figure 17.3 The coronary veins.
Chapter 18
1. Figure 18.1 The conducting system of the heart.
2. Figure 18.2 The cardiac cycle.
Chapter 20
1. Figure 20.1 The blood vessels.
2. Figure 20.2 Layers of the blood vessels.
3. Figure 20.3 Comparison of an artery, vein and capillary.
4. Figure 20.4 Capillary network.
Chapter 21
1. Figure 21.1 The baroreceptors.
2. Figure 21.2 Blood pressure measurement.
Chapter 22
1. Figure 22.1 The lymphatic system and organs.
2. Figure 22.2 The lymphatic capillaries.
3. Figure 22.3 Lymph node.
Chapter 23
1. Figure 23.1 The respiratory organs.
2. Figure 23.2 Detailed structures of the respiratory tract.
3. Figure 23.3 The lower respiratory tract.
4. Figure 23.4 Bronchial tree.
Chapter 24
1. Figure 24.1 Boyle’s Law.
2. Figure 24.2 Inspiration and expiration.
Chapter 25
1. Figure 25.1 The respiratory centre.
2. Figure 25.2 Peripheral chemoreceptors.
Chapter 26
1. Figure 26.1 External respiration.
2. Figure 26.2 Gas exchange in the lungs.
3. Figure 26.3 Internal respiration.
Chapter 27
1. Figure 27.1 The upper and lower gastrointestinal tract.
2. Figure 27.2 The tongue.
3. Figure 27.3 Swallowing action.
4. Figure 27.4 The stomach.
Chapter 28
1. Figure 28.1 The small intestine.
2. Figure 28.2 The large intestine.
Chapter 29
1. Figure 29.1 The liver, gall bladder and pancreas.
2. Figure 29.2 Liver lobules.
3. Figure 29.3 Bile production and secretion.
Chapter 30
1. Figure 30.1 The pancreas.
Chapter 31
1. Figure 31.1 Digestion and absorption.
Chapter 32
1. Figure 32.1 A nephron.
2. Figure 32.2 Bowman’s capsule.
Chapter 33
1. Figure 33.1 External layers of the kidney.
2. Figure 33.2 Blood flow through the kidney.
Chapter 34
1. Figure 34.1 Blood supply to the ureter.
2. Figure 34.2 The urinary bladder.
3. Figure 34.3 The male urethra.
4. Figure 34.4 The female urethra.
Chapter 35
1. Figure 35.1 Renal filtration.
2. Figure 35.2 Renin‐angiotensin pathway.
Chapter 36
1. Figure 36.1 The left testis and epididymis.
2. Figure 36.2 Sagittal view of the penis and male pelvis.
3. Figure 36.3 The anatomy of the penis.
Chapter 37
1. Figure 37.1 The prostate gland.
Chapter 38
1. Figure 38.1 Spermatogenesis.
2. Figure 38.2 Primary and secondary sex characteristics.
Chapter 39
1. Figure 39.1 The female reproductive organs.
Chapter 40
1. Figure 40.1 The external female genitalia.
Chapter 41
1. Figure 41.1 The breast.
2. Figure 41.2 The breast and surrounding structures.
3. Figure 41.3 Lobules and ducts.
4. Figure 41.4 The axillary lymph nodes.
5. Figure 41.5 Breast lymph.
Chapter 42
1. Figure 42.1 Hormonal regulation of the changes in the ovary and uterus.
2. Figure 42.2 Changes in the concentration of anterior pituitary and ovarian h...
Chapter 43
1. Figure 43.1 The major endocrine glands.
2. Figure 43.2 The pituitary gland and surrounding structures.
Chapter 44
1. Figure 44.1 The thyroid and parathyroid glands.
2. Figure 44.2 Control of thyroid hormone production – negative feedback.
Chapter 45
1. Figure 45.1 The pancreas.
2. Figure 45.2 Insulin and glucagon effects on blood glucose.
Chapter 46
1. Figure 46.1 Bone remodelling.
2. Figure 46.2 Bone growth.
3. Figure 46.3 Osteon, Haversian canal.
Chapter 47
1. Figure 47.1 The skeleton: axial and appendicular.
2. Figure 47.2 Compact bone (long bone).
3. Figure 47.3 Short bone.
4. Figure 47.4 Flat bone.
5. Figure 47.5 Irregular bone.
6. Figure 47.6 Sesamoid bone.
Chapter 48
1. Figure 48.1 Joint types.
Chapter 49
1. Figure 49.1 Muscle tissues.
Chapter 50
1. Figure 50.1 The skin and associated structures.
2. Figure 50.2 Skin types.
3. Figure 50.3 The layers of the epidermis.
Chapter 51
1. Figure 51.1 The hair and associated glands.
2. Figure 51.2 The nails.
Chapter 52
1. Figure 52.1 Epidermal and deep wound healing.
Chapter 53
1. Figure 53.1 Summary of wound healing events.
Chapter 54
1. Figure 54.1 The eye.
2. Figure 54.2 The lacrimal apparatus.
Chapter 55
1. Figure 55.1 The ear.
2. Figure 55.2 The outer ear.
3. Figure 55.3 The middle ear.
4. Figure 55.4 The inner ear.
Chapter 56
1. Figure 56.1 Pathway of smell.
2. Figure 56.2 Olfactory epithelium and olfactory receptor cells.
3. Figure 56.3 The olfactory bulb (nerve).
Chapter 57
1. Figure 57.1 The tongue.
2. Figure 57.2 Taste.

This edition first published 2022
© 2022 John Wiley & Sons Ltd

Edition History
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Library of Congress Cataloging‐in‐Publication Data applied for:

Names: Peate, Ian, author.
Title: Anatomy and physiology for nursing and healthcare students at a glance / Ian Peate.
Other titles: Anatomy and physiology for nurses at a glance | At a glance series (Oxford, England)
Description: 2nd edition. | Hoboken, NJ : Wiley-Blackwell, 2022. | Series: At a glance series | Preceded by: Anatomy and physiology for nurses at a glance / Ian Peate, Muralitharan Nair. 2015. | Includes bibliographical references and index.
Identifiers: LCCN 2022007589 (print) | LCCN 2022007590 (ebook) | ISBN 9781119757207 (paperback) | ISBN 9781119757214 (adobe pdf) | ISBN 9781119757221 (epub)
Subjects: MESH: Anatomy | Physiological Phenomena | Handbook | Nurses Instruction
Classification: LCC QP40 (print) | LCC QP40 (ebook) | NLM QS 39 | DDC 612.0076–dc23/eng/20220222
LC record available at https://lccn.loc.gov/2022007589
LC ebook record available at https://lccn.loc.gov/2022007590

Cover Design: Wiley
Cover Images: © SEBASTIAN KAULITZKI/Getty Images, PIXOLOGICSTUDIO/Getty Images

Preface

I am delighted to have been asked to provide a second edition of Anatomy and Physiology for Nursing and Healthcare Students at a Glance. This popular revision aid has retained the user‐friendly approach that includes bite‐sized pieces of information and full‐colour diagrams that help students retain, recall and apply facts to their practice.

All health and care providers aim to offer care that is safe and effective. In order to care effectively for people (sick or well), it is essential to have an understanding of and insight into anatomy and physiology.

The human body is composed of organic and inorganic molecules organised at a variety of structural levels; despite this, an individual should be seen and treated in a holistic manner. If the healthcare professional is to provide appropriate and timely care, it is essential that they are able to recognise illness, take prompt action to deliver effective treatment and refer appropriately, ensuring that the person they offer care and support to is at the centre of all that they do.

Healthcare professionals are required to demonstrate a sound knowledge of anatomy and physiology with the intention of providing safe and effective nursing care. This is often assessed as a part of a programme of study using a number of assessment techniques. The overall aim of this concise text is to provide an overview of anatomy and physiology and the related biological sciences that can help to develop your practical skills and improve your knowledge with the aim of you becoming a caring, knowledgeable and compassionate provider of care. It is anticipated that you will be able to deliver increasingly complex care for the people you care for when you understand how the body functions.

As you begin to appreciate how people respond or adapt to pathophysiological changes and stressors, you will be able to understand that people (regardless of their age) all have unique biological needs. The integration and application of evidence‐based theory to practice is a key component of effective and safe healthcare. However, this goal cannot be achieved without an understanding of anatomy and physiology.

An additional chapter has been introduced, Anatomical Terms, emphasising the importance of understanding and using the correct anatomical terminology when making a description of body parts as a shared method of communicating between health and care staff. This new edition also includes clinical practice points which aim to encourage readers to relate the theoretical concepts described to practice.

Anatomy is associated with the function of a living organism and as such it is almost always inseparable from physiology. Physiology is the science dealing with the study of the function of cells, tissues, organs and organisms; it is the study of life.

Ian Peate
London

1
Anatomical terms

Schematic illustration of the standard anatomical position. — **Figure 1.1** **The standard anatomical position.**

Schematic illustration of anatomical terms. — **Figure 1.2** **Anatomical terms.**

*Source: Tortora GJ, Derrickson B. (2017) Tortora’s Principles of Anatomy and Physiology, 15th edn. Hoboken: Wiley*

Schematic illustration of anatomical planes. — **Figure 1.3** **Anatomical planes.**

*Source: Tortora GJ, Derrickson B. (2017) Tortora’s Principles of Anatomy and Physiology, 15th edn. Hoboken: Wiley*

Schematic illustration of body cavities. — **Figure 1.4** **Body cavities.**

*Source: Tortora GJ, Derrickson B. (2017) Tortora’s Principles of Anatomy and Physiology, 15th edn. Hoboken: Wiley, with permission from John Wiley & Sons.*

Table 1.1 The body cavities.

Cavity	Content
Dorsal	Cranial cavity: holds the brain Spinal cavity: includes spinal column and spinal cord
Ventral	Thoracic cavity: surrounded by the ribs and chest muscles, superior to the diaphragm and abdominopelvic cavity. Further divided into the pleural cavities (left and right) which contain the lungs, bronchi and the mediastinum which contains the heart, pericardial membranes, large vessels of the heart, trachea, upper oesophagus, thymus, lymph nodes and other blood vessels and nerves Abdominopelvic cavity: divided into the abdominal cavity and pelvic cavity. The abdominal cavity: is between the diaphragm and the pelvis, lined with a membrane, contains the stomach, lower part of the oesophagus, small and large intestines (apart from sigmoid and rectum), spleen, liver, gallbladder, pancreas and adrenal glands, kidneys and ureters. The pelvic cavity: contains the urinary bladder, some reproductive organs and the rectum

Cavity

Content

Dorsal

Cranial cavity: holds the brain
Spinal cavity: includes spinal column and spinal cord

Ventral

Thoracic cavity: surrounded by the ribs and chest muscles, superior to the diaphragm and abdominopelvic cavity. Further divided into the pleural cavities (left and right) which contain the lungs, bronchi and the mediastinum which contains the heart, pericardial membranes, large vessels of the heart, trachea, upper oesophagus, thymus, lymph nodes and other blood vessels and nerves
Abdominopelvic cavity: divided into the abdominal cavity and pelvic cavity. The abdominal cavity: is between the diaphragm and the pelvis, lined with a membrane, contains the stomach, lower part of the oesophagus, small and large intestines (apart from sigmoid and rectum), spleen, liver, gallbladder, pancreas and adrenal glands, kidneys and ureters.
The pelvic cavity: contains the urinary bladder, some reproductive organs and the rectum

Anatomical position

Those terms that are used to describe locations and positions reference a person in what is known as the anatomical position. The international standard anatomical position is standing upright as seen in Figure 1.1; whenever referring to anatomical terms, always apply them to the person standing in the anatomical position. By using this as a standard posture for anatomical descriptions, confusion can be avoided even when in reality the person is in some other position.

The position is defined as if the body is standing erect with hips and knees extended, head forward facing, eyes open looking directly forwards with the mouth closed. The arms are by the sides (shoulders adducted), the palms are facing forward (elbows extended and wrists supinated), and the feet together. In this position, the radius and ulna are parallel.

Anatomical terms

It is important to understand and use anatomical terminology when making a description of body parts so there is a shared method of communicating (a common language) with nurses, doctors and other healthcare staff. This is done in order to accurately describe anatomical locations irrespective of their language. Knowing about anatomical terms makes things safer and clearer and will save time.

Anatomical terms (using a specific vocabulary) describe the directions within the body and also the body’s reference planes, cavities and regions (Figure 1.2). There are a number of occasions when a nurse or other healthcare worker is required to record information in nursing or medical notes with the intention of communicating with others or telling others the exact body part or location. Standard terms for describing human anatomy including the body and its organs are required to do this.

Directional terms

Directional terms describe the positions of structures relative to other structures or locations in the body.

When referring to left and right, reference is being made to the left and right side of the person standing in the anatomical position, not to the left and right side of the observer.

Anterior (also called ventral) refers to the front of the body and posterior (dorsal is also used) to the back of the body. The nipples, for example, are on the anterior (ventral) surface of the body, the buttocks are superior (dorsal).

Superior means above, towards the head, and inferior means below, towards the feet. The umbilicus is superior to the genitalia but inferior to the head.

Proximal and distal are only used to describe two points on the same arm or leg. Proximal means close to where the arm or leg is inserted into the body. Distal means further away from where the arm or leg is inserted into the body. The knee is proximal to the ankle as the knee is closer to where the leg inserts into the body. With regard to the arm, the wrist is distal to the elbow as the wrist is further away from where the arm inserts into the body.

Medial refers to any point that is closer to the midline of the body and lateral means any point further away from the midline. The midline is an imaginary line that separates the body in half vertically. The inner thigh is medial and the outer thigh is lateral.

Planes

To describe the anatomical positions of the internal structures, planes or sections are used (Figure 1.3). There are four planes.

Sagittal
Frontal
Transverse
Oblique

The sagittal, vertical (top to bottom) plane divides the body into left and right sides. It is known as a midsagittal plane when it divides the body down the middle into equal left and right sides. If the divide does not pass exactly midline, this is known as parasagittal. The frontal plane divides the body into anterior (ventral) and posterior (dorsal) portions. The transverse plane divides the body into superior and inferior portions. The oblique plane is a slanted plane (at an angle) passing through the body.

Body cavities

These areas contain internal organs. The two main cavities are the dorsal and ventral cavities (Figure 1.4). The dorsal cavity (sometimes called caudal) is on the posterior of the body, containing the cranial cavity and spinal cavity. The ventral cavity is on the anterior of the body, divided into the thoracic cavity and abdominopelvic cavity; the diaphragm divides the ventral cavity into two subcavities: thoracic and abdominal (Table 1.1).

2
Genetics and genomics

Schematic illustration of DNA and RNA. — **Figure 2.1** **DNA and RNA.**

Table 2.1 Types of RNA.

Type of RNA	Description
Messenger RNA (mRNA)	Copies portions of genetic code, a process known as transcription, and transports these copies to ribosomes, the cellular factories that facilitate the production of proteins from this code
Transfer RNA (tRNA)	Responsible for bringing amino acids, basic protein building blocks, to these protein factories, in response to the coded instructions introduced by the mRNA. This protein‐building process is called translation
Ribosomal RNA (rRNA)	The protein builder of the cell, without which protein production would not occur

Schematic illustration of mitosis. — **Figure 2.2** **Mitosis.**

Schematic illustration of meiosis. — **Figure 2.3** **Meiosis.**

Schematic illustration of fertilisation. — **Figure 2.4** **Fertilisation.**

Genetics is the study of the way particular features or diseases are inherited through genes passed down from one generation to the next. The idea of having a single gene for this or a single gene for that (determining fate) is not a good way of describing the complexity of genes. There are groups of genes that work together, influenced by a variety of environmental and other factors. The genome can be seen as the body’s instruction manual, with a copy of it in almost every healthy cell in the body. The study of the genome and the technologies that are required to analyse and interpret it is known as genomics.

DNA and RNA

Both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are made of nucleotides (bases) which are the building blocks, responsible for the storage and reading of genetic information that underpins all life. DNA encodes all genetic information, also acting as a biological store allowing the blueprint of life to be passed between generations. RNA reads and then decodes what is stored. This is a multistep process with specialised RNAs for each step (Table 2.1).

DNA and RNA are nucleic acids, known as linear polymers, consisting of sugars, phosphates and bases, but there are differences between the two. The differences permit the two molecules to work together, fulfilling essential roles. See Figure 2.1 for the differences. The complementary base pairs in DNA are adenine (‘A’), thymine (‘T’), guanine (‘G’) and cytosine (‘C’) and RNA shares adenine (‘A’), guanine (‘G’) and cytosine (‘C’) with DNA, but contains uracil (‘U’) instead of thymine (Figure 2.1).

Molecules in DNA have an even and uniform shape while in RNA they are uneven and diverse shapes. DNA molecules are made up of millions of nucleotides and RNA molecules are usually smaller, composed of hundreds to a few thousand nucleotides.

Mitosis, meiosis and fertilisation

The human cell usually has 46 chromosomes: 44 autosomes, which are paired, and two sex chromosomes, usually specifying whether someone is male (usually XY) or female (usually XX). Autosomes, known as homologous chromosomes, have all of the same genes arranged in the same order, However, there are small differences in the DNA letters of the genes.

Mitosis occurs when cells divide to make more cells or reproductive cells (meiosis), and when reproductive cells join to make a new individual (fertilisation).

Mitosis

Prior to a cell dividing to make two cells, all of its chromosomes are copied, known as sister chromatids. Until cell division, the copies stay connected with each other by their middles (centromeres.) Upon cell division, the copies are pulled apart, each new cell getting one identical copy of each chromosome. Every cell has an identical set of chromosomes (see Figure 2.2).

Meiosis

When egg and sperm cells form, they go through a type of cell division called meiosis. Meiosis reduces the number of chromosomes by half as well as creating genetic diversity. The cell copies each chromosome, unlike in mitosis, homologous chromosome pairs align, exchanging pieces (recombination). Recombination increases genetic diversity by adding pieces of slightly different chromosomes together. The recombined homologous chromosomes are divided into two daughter cells. Then the sister chromatids are pulled apart into a total of four reproductive cells. Each of these cells has one copy each of 23 chromosomes; all possess a unique combination of gene variations (Figure 2.3).

Fertilisation

Egg and sperm cells have 23 chromosomes each, half as many chromosomes as regular cells. Through the process of fertilisation, egg and sperm join, making a cell with 46 chromosomes (23 pairs), a zygote. For each chromosomal pair, one homologous chromosome came from each parent. Genes are arranged in the same order but there are small variations in the DNA letters of those genes (Figure 2.4).

3
Homeostasis

Schematic illustration of components of a negative feedback system. — **Figure 3.1** **Components of a negative feedback system.**

Schematic illustration of negative feedback – raised blood pressure. — **Figure 3.2** **Negative feedback – raised blood pressure.**

Schematic illustration of negative feedback – raised temperature. — **Figure 3.3** **Negative feedback – raised temperature.**

Schematic illustration of positive feedback of childbirth. — **Figure 3.4** **Positive feedback of childbirth.**

Homeostasis

Homeostasis is an important physiological concept and can be defined as the ability of the body or a cell to seek and maintain a condition of equilibrium within its internal environment when dealing with external changes. It is a state of equilibrium for the body. Homeostasis allows the organs of the body to function effectively in a broad range of conditions.

All the organs and organ systems of the human body work together in harmony and are closely regulated by the nervous and endocrine systems. The nervous system controls almost all body activities and the endocrine system secretes hormones that regulate these activities. Working together, the organ systems supply body cells with all the substances needed and also eliminate waste. They also keep temperature, pH, blood glucose and other conditions at just the right levels required to support life processes.

Temperature at 36.5 °C
Blood glucose – 4–8 mmol/L
pH of the blood – 7.4

Feedback mechanisms

There are a variety of feedback mechanisms used by the body to regulate internal systems. There are three fundamental elements associated with the feedback system: a receptor, a control centre and an effector (Figure 3.1). The effector may be a muscle, organs or another structure that receives messages indicating a reaction is required.

Receptor

The receptor senses changes in the internal environment, relaying information to the control centre. Specific nerve endings in the skin, for example, sense a change in temperature, detecting changes such as a sudden increase or fall in body temperature.

Control centre

The brain is the control centre, receiving information from the receptor and interpreting the information, and then sending information to the effector. The output could be nerve impulses or hormones or other chemical signals.

Effector

An effector is a body system, for example, the skin, blood vessels or the blood, that receives the information from the control centre, producing a response to the condition. For example, in the regulation of body temperature by our skin (if it drops below normal), the hypothalamus acts as the control centre, which receives input from the skin. The output from the control centre goes to the skeletal muscles via nerves to initiate shivering and this raises body temperature.

Negative feedback

Most body systems work on negative feedback. Negative feedback ensures that, in any control system, changes are reversed and then returned back to the set level. An example might be, if the blood pressure increases, then receptors in the carotid arteries detect this change in blood pressure and relay a message to the brain. The brain will cause the heart to beat more slowly and, by doing this, work towards decreasing the blood pressure. Decreasing heart rate has a negative effect on blood pressure (Figure 3.2). Another example of negative feedback is regulation of body temperature at a constant 37 °C. If we get too hot, blood vessels in the skin vasodilate and heat is lost and we cool down. If we get too cold, blood vessels in the skin vasoconstrict, we lose less heat and the body warms up. The negative feedback system therefore ensures that homeostasis is maintained (Figure 3.3).

Positive feedback

This is the mechanism used by the body to enhance an output needed to maintain homeostasis. Positive feedback mechanisms push levels out of normal ranges. While this process can be beneficial, it is rarely used by the body because of the risk of the increased stimuli becoming out of control.

An example of positive feedback is the release of oxytocin (a hormone) to increase and keep the contractions of childbirth happening as long as needed for the child’s birth. Contractions of the uterus are stimulated by oxytocin, produced in the pituitary gland in the brain, and the secretion of it is increased by positive feedback, increasing the strength of the contractions (Figure 3.4).

Another example of positive feedback occurs in lactation, during which the mother produces milk for her child. During pregnancy, levels of prolactin (a hormone) increase. Prolactin normally stimulates milk production but during pregnancy, progesterone inhibits milk production. At birth, when the placenta is released from the uterus, levels of progesterone drop and as a result, milk production flows. As the infant feeds, its suckling stimulates the breast, promoting further release of prolactin, producing even more. This positive feedback ensures the infant has sufficient milk during feeding. When the baby is weaned and is no longer breast feeding, stimulation stops, with prolactin in the mother’s blood returning to pre‐breastfeeding levels.