KNOW YOUR BODY The Essential Guide to Human Anatomy & Physiology

A Message from the Body

Some say I am the most fantastic machine in existence, because unlike most machines that can only do one or two jobs at a time, I can perform many tasks simultaneously - and I’m going to let you in on my secrets! Unlike other machines, I don’t come with spare parts, so I hope this book will inspire you to do everything you can to keep me running in tip-top condition. My basic needs are quite simple - good quality fuel in the form of nutritious food, pure water, rest, exercise (and some fun!), will keep me operating smoothly and prevent me from getting gunged up and breaking down unnecessarily.

The study of the structure and relationship between my body parts is termed ‘anatomy’ while ‘physiology’ is the study of how all these parts function together. ‘Pathology’ looks at the causes, mechanisms and consequence of dis-ease that impairs my normal functioning and typically manifests with various ‘abnormal’ signs and symptoms. ‘Homeostasis’ - homeo (unchanging) + stasis (standing) - refers to my ability to seek and maintain a condition of internal equilibrium or stability when dealing with external changes. For example, I sweat to cool off during the hot summer days and I shiver to produce heat when I’m cold.

At a chemical level, I’m made up of tiny building blocks called atoms – apparently around 7,000,000,000,000,000,000,000,000,000 (7 octillion) as an adult! Atoms such as carbon, hydrogen, oxygen and nitrogen are essential for keeping me alive, and combine to form molecules such as fats, proteins and carbohydrates. These molecules then combine to form cells, which are my basic structural and functional units. I am made up of many different types of cells, each with specific functions, but more about that later!

My cells combine to form four tissue types – epithelial, muscular, connective and nervous - and my various organs are composed of at least two types of tissue - for example, my heart is made up of all four tissue types. Organs with a common function make up my systems that perform particular activities - for example, my digestive system is composed of organs such as the stomach, liver, pancreas, small intestine and large intestine, and it functions to break down and digest my fuel (food). All of my systems combine to form me - the human organism.

My body systems include the integumentary, skeletal, muscular, cardiovascular, lymphatic, respiratory, digestive, nervous, endocrine, urinary and reproductive systems. Each of my systems depends on the others - either directly or indirectly - and they all interrelate to ensure that I function normally. My integumentary system, composed of my skin, hair and nails, protects my internal structures from damage, stores fat, prevents dehydration and produces vitamins and hormones. The bones, joints, ligaments, tendons and cartilage of my skeletal system support and protect, giving me shape and form. My skeletal, muscular and nervous systems work together enabling me to move, while internal muscles enable my heart to beat and my organs and vessels to contract and relax for internal movement. My respiratory system ensures that I receive a steady supply of oxygen, which is delivered to all my cells and tissues by my cardiovascular system. My digestive system breaks food down into smaller particles that I can absorb, and these are delivered to all my cells and tissues by my cardiovascular system. My lymphatic and urinary systems both work to keep my body fluids healthy and balanced, as well as removing waste. My endocrine organs secrete hormones that regulate many internal processes including growth, homeostasis, metabolism, sexual development and reproduction. My brain receives information from all body systems to ensure my proper functioning, and my amazing nerves extend to all parts, including my muscles and internal organs. And just like the white pith inside a citrus fruit that holds all its cells and segments together, layers of connective tissue hold all my internal bits and pieces in place, running through my entire body from my head to my toes.

As you study my anatomy and physiology, I want to make sure you are viewing me from the correct perspective, so I’d like you to do a little exercise. Stand up, looking straight ahead with your feet together, and let your arms hang by your sides with your palms facing forward. You are now in the ‘anatomical position’, and whenever you see an anatomical drawing the body is assumed to be in that position. The ‘midline’ is an imaginary line that runs right through the centre of the body, dividing it into right and left sides. Health care practitioners and body workers use anatomical terms of location when they discuss patients or make notes that they or other practitioners may need to refer to, and their descriptions involving anatomical features are usually framed with this position in mind. In the medical field, it’s important for everyone to have the same frame of reference - especially during a medical procedure - otherwise it could be disastrous if the people involved didn’t understand directions given to them by their colleagues. My anatomical position puts everyone on the same page.

In your studies, you will come across many anatomical descriptive terms and an understanding of these can make things easier. Many of the words used to describe human anatomy and physiology derive from Latin. If you take each word apart, you can often work out the meaning. Here are examples of some common word parts that you will come across when studying the structure and function of the human body in health and disease:

a- lack of

mal- abnormal

adren- towards the kidney

mamm- of breast

angi- vessel

mast- of breast

angin- choked feeling

medull- middle

anti- opposed to

melan- black

ante- before, preceding

micro- small

arth- of joints

myle- of spinal cord or bone marrow

auto – self generated

myo- muscle

basal- base

neo- new

bi- having two


nephro- kidney

bili- of bile

neuro- nerve

brachi- of the arm

olfact- smell

brady- slow

osteo- of bone

brev- brief or short

oxy- oxygen

broncho- of the bronchi

pect- breast area

carcin- cancer

peri- around

cephal- of the head

phleb- vein

cerebro- of the brain

poly- many

chrondo- of cartilage

pulmo- of the lungs

cili- small hair

ren- of kidney

contra- against

sclero- hard

cort- outer layer

seb- grease

cyan- blue

sphin- squeeze

cyst- bladder or sac

sub- beneath

de- removal or reversal

super/supra- above

dia- between

systol- contraction

dialys- break apart or separate

tachy- rapid

diastol- stand apart

tetan-rigid

dors- the back

thromb- clot

ec/ex- outside

trans- across

entero- of the intestine

tri- three

eryth- red

tuber- swelling

fasci- bundle

tunic- covering

gastr- of the stomach

-able capable of

glosso- of the tongue

-algia pain in

glute- of the buttock

-cide destroy/kill

haem- of the blood

-cyte cell

hepat- of the liver

-ectomy cut out

hiat- gap

-itis inflammation

hist- of tissue

-malacia softening of

hyper- excess

-oma tumour

hypo- below

-phil to love

jugul- of the throat

-phragm partition

lact- of milk

-rrhagia excessive discharge

leuco- white

-rrhea flow or discharge

leva- to raise

-stalsis compression

macro- large

-stasis to fix

PICTURE INSERTED HERE IN BOOK SHOWING ANATOMICAL POSITIONS

To understand my ‘anatomical planes’, imagine me standing in an upright position, and now imagine dissecting me with vertical and horizontal lines. The lateral or sagittal plane is an imaginary vertical line that runs from front to back or back to front, dividing me, or one of my organs, into right and left regions. If the vertical plane runs exactly down the middle, it’s referred to as the median or mid-sagittal plane, while the parasagittal plane divides me, or one of my organs, into unequal right and left regions.

The frontal or coronal plane is a vertical plane that runs through my centre from top to bottom, dividing me, or one of my organs, into front (anterior) and back (posterior) regions.

The transverse plane is a horizontal plane dividing me, or one of my organs, into upper (superior) and lower (inferior) regions. Dividing horizontally does not mean two equal divisions but can go anywhere to create cross sections.

My skeleton has two major components – my axial skeleton consisting of 80 bones located along the axis of my body, and my appendicular skeleton consisting of the 126 bones of my appendages (limbs) and girdles (shoulder and pelvic girdles).

Just like on a map, my ‘regions’ refers to certain body areas. In my axial area, the head and neck regions include: cephalic (head), cervical (neck), cranial (skull), frontal (forehead), occipital (back of head), ophthalmic or orbital (eyes), oral (mouth) and nasal (nose). My thoracic regions are axillary (armpit), costal (ribs), mammary (breast), pectoral (chest) and vertebral (backbone), while my abdominal regions are celiac (abdomen), gluteal (buttocks), groin/inguinal (area of abdomen near inner thigh), lumbar (lower back), pelvic (lower part of abdomen), perineal (between anus and external genitalia) and sacral (end of spine). In my appendicular area, my arm regions are termed brachial (arm), carpal (wrist), cubital (elbow), forearm (lower arm) and palmar (palm), while my leg regions are femoral (thigh), lower leg (below knee), pedal (foot) and popliteal (back of knee).

My ‘cavities’ are the spaces that hold my internal organs, my two main cavities being my dorsal and my ventral cavities. My dorsal cavity is subdivided into the cranial cavity housing my brain, and the spinal cavity housing my spinal cord. My ventral cavity houses the rest of my organs and is subdivided into the thoracic cavity containing my heart and lungs, and the abdomino-pelvic cavity containing the organs of my abdomen and pelvis.

PICTURE INSERTED HERE IN BOOK SHOWING REGIONS OF ABDOMEN

My abdomen is also divided into nine ‘regions’ and four ‘quadrants’ (quarters). The epigastric region is in the centre, just above my navel, on or over my stomach. The hypochondriac region (hypo = below; chondral = cartilage) lies to the right and left of my epigastric region, just below the cartilage of my ribcage. The hypogastric region is in the centre, below my stomach and navel, while the iliac region lies to the right and left of this, close to my hipbones. My umbilical region is the area around my navel, and my lumbar region forms the area of my lower back to the right and left of my umbilical region. An imaginary cross on my abdomen passing through my navel divides my abdomen into four quadrants – the right and left upper quadrants and right and left lower quadrants. Whenever I suffer from abdominal pain, the medical practitioner checks these areas to determine what organ might be affected.

The term disease refers to any condition that causes pain, dysfunction, distress or death to the afflicted person. Diseases can affect people not only physically but also mentally, as contracting and living with a disease can alter a person’s perspective on life. Diseases are generally classified as infectious diseases that can be transmitted to others, deficiency diseases due to lack of nutrients in the diet, hereditary diseases (both genetic and non-genetic), physiological diseases in which a particular abnormal condition affects the functioning of the body, and neuropsychiatric disorders encompassing a broad range of medical conditions that involve both neurology and psychiatry e.g. seizures, eating disorders, depression, anxiety. A disease that is of uncertain or unknown origin is termed ‘idiopathic’. Death due to ageing in the absence of a specific disease is generally termed ‘death by natural causes’.

Diseases can also be classified in other ways, such as communicable versus non-communicable diseases. Communicable diseases - also known as infectious or transmissible diseases - are illnesses that result from infection by pathogenic (disease causing) organisms e.g. bacteria, viruses etc. and can be transmitted to others. Non-communicable diseases - also known as chronic diseases - tend to be of long duration and can result from a combination of genetic, physiological, environmental and behavioural factors. They include cardiovascular diseases (e.g. heart attack and stroke), cancers, chronic respiratory diseases and diabetes. Pathology - the study of disease - also includes the study of its aetiology, or cause. The terms ‘contagious’ and ‘infectious’ sometimes cause confusion. Contagious diseases are spread by contact, while germs such as bacteria or viruses that get into the body leading to problems, cause infectious diseases. Infectious diseases that spread from person to person are said to be contagious, but something infectious isn’t always contagious e.g. you can be infected with food poisoning, which in itself is not contagious. A zoonotic disease is a disease that is spread from animals to humans e.g. bird flu, brucellosis, anthrax.

The terms disease, disorder, syndrome and condition are often used interchangeably but there are some subtle differences, and describing these is sometimes difficult. The word ‘disease’ is normally used in the sense of a sickness or illness due to external or internal factors e.g. cardiovascular disease can cause both physical and emotional signs and symptoms, as well as pain, dysfunction, distress or death. A ‘disorder’ is regarded as a disruption to the normal or regular functions in the body - or a part of the body - due to disease e.g. a disorder resulting from cardiovascular disease is an arrhythmia or irregular heartbeat, which is not a disease in itself, but a problem that occurs as a result of having cardiovascular disease.

A ‘syndrome’ is a collection of signs and symptoms that characterise a particular medical condition or disease e.g. Down syndrome is a well-known genetic syndrome that is characterised by having an extra copy of chromosome 21, in combination with a number of distinctive physical features at birth. Sometimes a syndrome can be caused by a number of diseases, or it can be a medical ‘condition’ itself. A ‘condition’ is sometimes described as an abnormal state of health that interferes with usual activities or affects wellbeing e.g. chronic fatigue syndrome is a neurological condition diagnosed from a collection of symptoms, as well as the main symptom of exhaustion following physical activity.

Health and wellbeing can be affected by many factors - often referred to as risk factors. A risk factor is something that may increase a person’s susceptibility to disease, and includes things such as behaviour, genetics, lifestyle, age, gender, social factors, disability and environmental factors. For example, physical inactivity can, over time, be a risk factor for weight gain, high blood pressure and high cholesterol levels.

The terms ‘sign’ and ‘symptom’ are often used interchangeably when discussing disease, but there are differences. Visible evidence of a disease such as a skin rash or a cough is a sign, while back pain, headache and fatigue are symptoms and can only be recognised by the person experiencing them. Some things can be signs as well as symptoms e.g. a person in pain who is writhing in agony. ‘Red flag’ signs and symptoms refer to those that may indicate a more serious underlying pathology and should always be medically investigated e.g. abnormal discharges, blood in the urine or sputum, breast lumps, changing moles or lumps on the skin, breathlessness, bone pain, persistent cough, etc. ‘Prognosis’ refers to the likely outcome of a disease or ailment, including whether the signs and symptoms will improve, worsen or remain stable over time. For example, the prognosis for melanoma (skin cancer) is good if it is detected and treated before it spreads.

According to Professor Daniel Lieberman of Harvard University, many modern-day diseases, which he calls ‘mismatch diseases’, are caused by a discrepancy between contemporary lifestyles and the original hunter-gatherer purposes for which the human body evolved. Examples include the rise of type 2 diabetes and cardiovascular disease, and he states that some of the main culprits are lack of movement, excess sugar in the diet, poor sleep and stress. Dr. Lieberman says that we could avoid most of these diseases by making different lifestyle choices. In an article published by the “European Scientist” regarding the COVID-19 pandemic, UK cardiologist, Dr. Aseem Malhotra echoes this. Dr. Malhotra states that “obesity and chronic metabolic disease is killing COVID-19 patients: now is the time to eat real food, protect the National Health Service and save lives… the elephant in the room is that the baseline general health in many western populations was already in a horrendous state to begin with.”

Each of us has our own unique constitution or physical makeup with respect to the health, strength and appearance of our bodies. The term ‘constitutional rhythm’ is sometimes used to describe the particular patterns of a person’s body or mind that are unique to that person. We each have our own ‘rhythm’ that feels ‘normal’ to us and we can sense there is something wrong if this rhythm suddenly changes e.g. sudden changes in bowel movements, weight, sleep, appetite etc. usually prompt us to seek medical advice and attention.

I hope that I haven’t bored you with all this ‘jargon’ and that it will prove useful in your studies. As you continue your journey inside the body, I hope that you will realise what a wonderful, complex and clever creation the human body is, and become inspired to make wise choices that can improve your own health and wellbeing. Knowledge is empowerment and the more we know about the workings of our own bodies, the more capable we become at making better lifestyle choices to improve the quality of our lives. ‘Health is wealth’ and the body really is our most valuable possession in life!

(MY BOOK CONTAINS 473 PAGES & HAS AN ACCOMPANYING WORKBOOK FULL OF TESTS, CROSSWORDS, WORD SEARCHES etc. )