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Human Biology Enabling Course –

Module 1

Introduction to the Human Body

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May 2011

Endeavour College of Natural Health Enabling Course: Human Biology Module 1

Contents 1 General introduction

1.1 Welcome 1.2 Module aims 1.3 How to use these modules 1.4 How to study anatomy and physiology 1.5 Key words 1.6 Activity 1.7 What you will need to complete this course

2 Introduction to anatomy and physiology 2.1 Prokaryotes 2.2 Eukaryotes 2.3 Anatomy & Physiology defined

3 Levels of organisation 3.1 Chemical level 3.2 Cellular level 3.3 Tissue level 3.4 Organ level 3.5 System level 3.6 Organism level

4 Basic life processes 4.1 Metabolism 4.2 Responsiveness 4.3 Movement 4.4 Growth 4.5 Differentiation 4.6 Reproduction

5 Homeostasis 5.1 How it works 5.2 Negative feedback loop

5.3 Positive feedback loop

6 Basic anatomical terminology

6.1 Anatomical position

6.2 Directional terms

6.3 Regional names

6.4 Activity

6.5 Planes and sections

6.6 Activity

6.7 Abdominopelvic regions and quadrants

6.8 Activity

6.9 Body cavities

7 References


Module 1 – Introduction to the Human Body

1 General Introduction

1.1 Welcome

Welcome to the Human Biology enabling modules at the Endeavour College of Natural Health. You are reading this module because you have enrolled in a Bachelor of Health Science degree specialising in a complementary medicine modality such as Naturopathy or Acupuncture. Today, the complementary medicine practitioner is expected to have a working knowledge of human physiology, biochemistry and pharmacology. These areas are all underpinned to some extent by an understanding of anatomy and physiology principles.

Generally we like a good story and the human body is no exception. If the study of human

anatomy and physiology is approached with intention of learning the story behind the

structure and function, common stumbling blocks such as the terminology and amount of

information become much easier to assimilate. In fact, approached with a sense of wonder,

learning anatomy and physiology is awe inspiring especially if you relate what you are

learning to your everyday life.

1.2 Module aims

By the end of the modules you will have foundation for building a human body. Most

importantly you will know some basic anatomical terminology and have enough information

to assist you with a smooth transition into your semester one studies in anatomy and

physiology.

1.3 How to use these modules

There are four modules which follow the material covered in classes. Each module builds on

the other so we suggest that you complete them in order from 1-4. The emphasis is on a

‘picture tells a thousand words’, therefore, the modules include many diagrams and web

links for you to access to help the material written in the study guide make sense. There are

small activities incorporated into the modules and quiz questions to assist you to assimilate

the material.


1.4 How to study anatomy and physiology

To assist you in learning about the human body, especially as the science of anatomy and

physiology is so extensive, the following are pointers to make the task easier:

1. Approach anatomy and physiology as though you are learning a new language.

Memorise the terminology (in italics) and relate them to your own body.

2. Practice, especially labelling body parts/regions. Stand in front of a mirror and have

someone read out different areas and anatomical positions for you to find.

3. Connect each part of the story with the overall story. Anatomy and physiology for

study purposes is broken into bite sizes chunks, but stay focussed on the overall

function these parts play. In other words look for the why as well as the what.

4. As mentioned earlier a picture tells a thousand words. Use the web links and

animations to assist your understanding. You can also purchase extra resources

such as an anatomy and physiology colouring book which is fantastic to assisting

with memorising body structures.

1.5 Key words

Key words and definitions to get you started:

Biology: bio= life, living logy= study or science

cardi= heart

cerebro= brain

chondr = cartilage

crani= skull

derma= skin

epi= upon, on, above

endo= within, inside

hemi= half

micro= small

myo= muscle

osteo= bone

para= near

peri= around

pseudo= false

sub= under, beneath, below

itis inflammation

1.6 Activity

List the meaning of the following words – cardiology, microbiology, craniology and

osteomyelitis


1.7 What you will need to complete this course

Student number

Internet access

The textbook: Tortora, Derrickson: Principles of Anatomy and Physiology, 14th Edn

A notebook

Writing materials

2 Introduction to anatomy and physiology

The story of anatomy and physiology starts some 3000 million years ago in volcanic thermal

springs that contained a variety of chemical substances which were in the process of forming

complex molecules (Attenborough, 1984).

2.1 Prokaryotes

After an immense period of time the first microscopic living matter, the bacteria, were

produced. These bacterial cells, known as prokaryotes (pro-kary-OTES), were the first cells

to inhabit the planet. They had a very basic internal structure shown in figure 1.

Figure 1. Prokaryote (from http://www.biology.about.com)


2.2 Eukaryotes

Over time these early bacteria began to differentiate and specialise into a variety of cells

known as eukaryotes (u-kary-OTES) (Figure. 2). Cells of the same type started to combine

and form harmonious relationships leading to the development of specialised tissues.

Different tissues then combined giving rise to complex structures known as organs further

increasing the capacity for growth, development and specialisation such as groups of organs

that collectively make up a cardiorespiratory system (heart, lungs and tubes). As systems

became more advanced they eventually formed a vastly complex collection of systems

known as the human body the study of which is called human biology.

Figure 2. Eukaryote (from http://www.connect.in.com)

2.3 Anatomy & Physiology defined

The study of human biology that you are undertaking as part of your degree is the science of

human anatomy and physiology. Anatomy is concerned with the identification of structure

and relationship of the structures to one another. For example, within the cardiovascular

system, human biologists have mapped the relationship between the heart (cardio) that

pumps blood and the blood vessels (vascular) that carry the blood to all parts of the body.

Physiology on the other hand focuses on how body systems function. For example,

powerful microscopes have enabled the discovery of how cells replicate (mitosis) for growth

and development. Anatomy and physiology can therefore be summarised as the study of

structure and function.


3 Levels of organisation

Figure 3. Levels of organisation

3.1 Chemical level

If we look at the journey from pools of chemicals (atoms and molecules) in the volcanic

springs to a complete human body, what stands out is the ever increasing level of

organisation from basic structure and function to highly complex interacting systems. The

fascinating thing is that the wholeness in body structure that you see when you look in a

mirror still retains the basic building blocks of our earliest beginnings. In fact, remove the

atoms and molecules and you disappear.

Figure 4. Molecule (from http://www.people.eku.edu)


The smallest units of matter known as atoms are powerfully attracted to each other. When

different atoms combine they form molecules. For example, one of the most important

molecules in the human body is deoxyribonucleic acid or better known as DNA. Contained in

the nucleus of cells, DNA, houses our genetic heritage (genes), and is the blueprint for your

existence. The most prolific atoms that combine to form life giving molecules are carbon,

hydrogen, oxygen and nitrogen. Combinations of these important chemicals form the

essential components in human body cells, for example, the protective fatty membrane that

makes up cell walls. Other combinations of these key atoms include the protein that makes

up your muscle and the glucose that your body relies for energy. It seems there’s truth after

all in the saying ‘you are what you eat’.

3.2 Cellular level

Figure 5. Cell (from http://www.reshealth.org)

As molecules became more specialised they eventually formed harmonious relationships to

work collectively for the developing organism. In order to protect the developing molecules, a

protective barrier formed sealing them from harsh external environments. This sealed

package of specialised molecules is called a cell. Cells are the building blocks of the human

body and number in the trillions.

There are many different types of cells, for example, muscle cells that help you move, digest

your food and pump blood around your body. There are brain cells that control body

processes, skin cells that stop the contents of your body from entering the outside world and

liver cells that detoxify substances that enter your body. Each cell is like a factory of

important parts that function to maintain the life of the cell and, therefore, you. We will

explore them more in Module 2.


3.3 Tissue level

Figure 6. Tissues (from http://www.people.eku.edu)

A group of the same cell type that form harmonious relationships with a common function is

identified as a tissue. For example, in skeletal muscle (the tissue that contracts powerfully to

enable you to perform everyday functions) there are thousands of individual muscle cells,

each of which specialises in contraction and relaxation and when working collectively

generates enough power to move the whole body or lift a heavy weight. There are four main

tissues in the human body which we will explore in a later module. They are epithelial tissue

(e.g. skin, body cavity linings), connective tissue (e.g. cartilage), muscular tissue and

nervous tissue.

3.4 Organ level

Figure 7. Stomach (from http://www.pitt.edu.)

Two or more tissues with a common function are referred to as an organ. For example, the

stomach is a combination of muscle tissue that enables it to stretch after a meal and

epithelial (ep-i-THE- le-al) tissue which lines the inside of the stomach keeping the contents

inside.


3.5 System level

Figure 8. Digestive System (from http://www.nlm.nih.gov)

When several organs work together such as the stomach, gallbladder, and the small and

large intestine they collectively operate as the digestive system. In other words each organ

performs its unique function to enable a complex process to take place. In this case, it is the

breakdown and absorption of nutrients from the food we ingest.

3.6 Organism level

Figure 9. Human Body (from http://www.esoriano.wordpress.com)

The largest and final level of organisation in the human body is that of the whole organism

functioning as a collection of parts or systems.


4 Basic life processes

From the smallest level of organisation (chemical) to the largest (living organism) the human

body has some unique features that distinguish it from non-living material.

4.1 Metabolism

The human body is in a constant state of activity referred to as metabolism. Metabolism

involves two key processes; the first is catabolism which is the breaking down of substances

in the body such a food for energy or dismantling and recycling components of worn out red

blood cells. The other process is anabolism which is the building of new cells and tissues for

growth, development and maintenance of the human organism.

4.2 Responsiveness

Another distinguishing feature of living organisms is the ability to detect and respond to

changes both in the internal (e.g. invading bacteria) and external environment (e.g.

temperature).

4.3 Movement

The whole organism is in a constant state of movement during life, even if you lie perfectly

still your blood is circulating through your whole body which can be felt in your pulse.

4.4 Growth

Living systems grow in size and complexity due to the increase in the number and size of

cells, for example, from birth to adult.

4.5 Differentiation

Many cells in the body such as stem cells start as unspecialised or immature cells awaiting

instructions from the DNA/genes to begin developing (differentiation) into its mature state.

For example, immature bone cells are referred to as osteoblasts and the mature cell as an

osteocyte.

4.6 Reproduction

Living systems take part in reproduction, from the formation of new cells for growth and

repair and replacement of worn out cells/tissues to producing a new individual.


5 Homeostasis

The basic life processes covered in section 4 are highly regulated in the body. The human

organisation constantly attempts to return the system to one of balance when faced with

internal or external forces that threaten to disrupt the life process such as when the body

becomes too hot or cold. Maintaining a state of balance or equilibrium during a lifespan is

called homeostasis: homeo meaning ‘sameness’ and stasis ‘standing still’.

5.1 How it works

Homeostasis ensures the body’s internal environment (cells, tissues, organs, systems) stays

within an optimum range to maintain life. For example, the body has internal receptors

(specialised cells) that detect a rise in blood pressure (imbalance). To restore balance the

brain commands a release of certain hormones into the blood which causes the blood

vessels to widen (dilate) therefore returning blood pressure back to optimal levels. This

process is summarised in Figure 10.

Figure 10. Homeostasis


5.2 Feedback loops

The capacity to detect and respond to disruptions in homeostasis occurs through specialised

pathways in the body’s nervous system called feedback loops. Feedback loops convey vital

information signals to the brain for interpretation and processing. For example, if you

consume a large meal special receptors in the stomach wall send a signal to the brain

indicating that homeostasis may be threatened causing sickness. The brain responds with

generating a feeling of fullness in an attempt to stop further consumption of food.

In the example of overeating the feedback loop is considered to be negative feedback, as

the brain signals a reverse of the stimulus that threatens homeostasis (overeating). If the

brain issues a signal to increase the stimulus it is called a positive feedback loop. An

example of positive feedback is demonstrated during childbirth (labour). The contraction of

the uterus (stimulus) signals to the brain to produce a hormone called oxytocin which further

increases the rate and extent of contractions until the expulsion of the baby. Positive and

negative feedback loops are shown in Figure 11.

Figure 11. Negative Feedback Loop Positive Feedback Loop


Homeostatic imbalance can lead to disease and death. Given the important role it plays in

maintaining basic life processes; homeostasis is a reoccurring theme throughout your

course.

6 Basic anatomical terminology

6.1 The anatomical position

To ensure consistency across scientific disciplines, a common language is used with regard

to referencing of positions and regions on the human body. This is referred to as anatomical

terminology.

In the anatomical position the subject is:

Standing upright

Facing the observer

Head is level

Eyes are facing forward

Feet are flat on the floor

Arms at sides

Palms facing forward


6.2 Directional terms

As observed in Figure 12 various directional terms are used to locate one part of the body in

relation to another:

Figure 12. Anatomical position (from http://www.emergencymedicaled.com)

Superior is towards the head.

Inferior is away from the head.

Dorsal/posterior is back of the body (think of a dorsal fin on a shark).

Ventral/anterior is the front of the body.

Medial is nearer the midline of the body.

Lateral is further away from the midline (imagine a vertical line down the middle).

Proximal is nearer the attachment of the limb to the body (e.g. the knee is proximal

to the ankle).

Distal is further away from the attachment of the limb to the body (e.g. the wrist is

distal to the elbow).

Body positions:

Prone is lying face down (e.g. sleeping on your stomach).

Supine is lying face up (e.g. sleeping on your back).

http://www.emergencymedicaled.com/


6.3 Regional names

Figure 13. Regional names

Regional names are given to specific regions of the body for reference:

Cranial (skull)

Thoracic (chest)

Brachial (arm)

Patellar (knee)

Cephalic (head)

Gluteal (buttock)

6.4 Activity Activity: Find the regions listed above in Figure 13.


6.5 Planes and sections

Figure 14. Directional planes

Dividing the body into planes and sections provides reference points for imaging techniques

such as CT and MRI scans where thin slices of body parts are examined.

Refer to Figure 14 to identify the midsagittal, frontal/coronal, transverse and oblique planes

on the body.

6.6 Activity Activity: stand in front of a mirror and practice drawing an imaginary line through the various

planes of your body.


6.7 Abdominopelvic regions and quadrants

Figure 15. Regions Quadrants

Dividing the abdominal area into regions and quadrants allows anatomists and medical

clinicians to locate organs for reference.

Figure 15 shows the abdominal section of the body divided into regions and quadrants.

6.8 Activity Activity: If a patient presents with abdominal pain below their left breast:

1. What is the quadrant and region called?

2. What organs are located there?


6.9 Body cavities

Figure 16. Body Cavities

Cavities or hollows in the body are divided into dorsal which contains the cranial and

vertebral cavity and the ventral which houses the thoracic and abdominopelvic cavities.

These cavities are covered with a slippery lining called serous membranes that coats the

cavity walls and the organs contained within, for example, the lungs are covered by pleura,

the heart by pericardium, and the abdominal organs by the peritoneum.

The serous membrane that lines cavity walls is called the parietal layer and that which lines

the organ is known as the visceral (organ) layer.


7 References

Attenborough, D, 1984. The Living Planet, British Broadcasting Corporation, Britain.

Tortora, GJ, Derrickson, B, 2012. Principles of Anatomy and Physiology, 13th edn, John

Wiley & Sons, Inc, USA.

Winston, R, 2004. Human, DK Publishing, London.

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