HBA Notes

Topics Covered:

Week 1: Introduction to the Human Body

Week 2: Cell Structure and Function

Week 3: Movement of Molecules

Week 4: Nervous System

Week 5: Homeostasis and Endocrine

Week 6: The Heart

Week 7: Cardiovascular System

Week 8: Respiratory System

Week 9: Digestion and Metabolism

Week 10: Renal System

Week 11: Reproductive System and Acid-Base

Week 1: Introduction to the Human Body

Textbook readings: 2-5, 17-20 up to medical imaging, homeostasis 8-12

Learning Objectives:

1. Define anatomy and physiology

2. List the different levels of structural organisation in the body

3. Briefly describe the major functions of the major organ systems

4. List the major body cavities and their subdivisions

5. List the major classes of organic molecules in the body and provide a brief description of

their functions

6. Define homeostasis and describe the importance of homeostasis

Anatomy: The science of body structures and the relationships among them (first studied by

dissection)

Physiology: The science of body functions – how the body parts work

Chemical Level: (letters of the alphabet)

- Includes atoms (the smallest units of matter that participate in chemical reactions) and

molecules (2 or more atoms joined together)

- E.g. DNA and glucose (commonly known as blood sugar)

Cellular Level: (words)

- Molecules combine to form cells, the basic structural and functional units of an organism

- Cells are the smallest living units in the human body

Tissue Level: (sentences)

- Tissues are groups of cells and the materials surrounding them that work together to

perform a particular function

4 Basic Types of Tissues in Human Body:

1. Epithelial tissue (covers body surfaces, lines hollow organs and cavities, forms glands)

2. Connective tissue (connects, supports, and protects body organs while distributing blood

vessels to other tissues)

3. Muscular tissue (contracts to make body parts move and generates heat)

4. Nervous tissue (carries information from one part of the body to another through nerve

impulses)

Organ Level: (paragraphs)

- At the organ level different types of tissues are joined together

- Organs are structures that are composed of 2 or more different types of tissues

- E.g. skin, bones

System Level: (chapter)

- A system consists of related organs (paragraphs) with a common function

- Sometimes an organ is part of more than one system (e.g. Pancreas: digestive and endocrine

systems)

Organismal Level: (book)

- Any living individual

- All the parts of the human body functioning together make up the total organism

Functions of Major Organ Systems:

Integumentary:

Functions: Protects body; helps regulate body temperature; detects sensations such as touch, pain,

warmth, and cold

Components: Skin and associated structures (e.g. hair, fingernails and toenails, sweat glands, and oil

glands)

Skeletal:

Functions: Supports and protects body; provides surface area for muscle attachments; aids body

movements

Components: Bones and joints of the body and their associated cartilages

Muscular:

Functions: Participates in body movements, such as walking; maintains posture; produces heat

Components: Skeletal muscle tissue - muscle usually attached to bones (other muscles tissues

include smooth and cardiac)

Nervous:

Functions: Generates action potentials (nerve impulses) to regulate body activities; detects changes

in body’s internal and external environments, interprets changes, and responds by causing muscular

contractions or glandular secretions

Components: Brain, spinal cord, nerves, and special sense organs (e.g. eyes and ears)

Endocrine:

Functions: Regulates body activities by releasing hormones (chemical messengers transported in

blood from endocrine gland or tissue to target organ)

Components: Hormone producing glands (e.g. hypothalamus, pituitary gland, thymus)

Cardiovascular:

Functions: Heart pumps blood through blood vessels; blood carries oxygen and nutrients to cells and

carbon dioxide and wastes away from cells and helps regulate acid-base balance, temperature, and

water content of body fluids; blood components help defend against disease and repair damaged

blood vessels

Components: Heart, blood, and blood vessels

Lymphatic:

Functions: Returns proteins and fluid to blood; carries lipids from gastrointestinal tract to blood;

contains sites of maturation and proliferation of B cells and T cells that protect against disease-

causing microbes

Components: Lymphatic fluid and vessels; spleen; thymus; lymph nodes; tonsils; cells that carry out

immune responses (e.g. B cells, T cells and others)

Respiratory:

Functions: Transfers oxygen from inhaled air to blood and carbon dioxide from blood to exhaled air;

air flowing out of lungs through vocal cords produces sounds

Components: Lungs, air passageways such as the pharynx (throat), larynx (voice box), trachea

(windpipe) and bronchial tubes leading into and out of the lungs

Digestive:

Functions: Achieves physical and chemical breakdown of food; absorbs nutrients; eliminates solid

wastes

Components: Mouth, pharynx, oesophagus, stomach, small and large intestines, and anus; also

includes accessory organs that assist in digestive processes such as salivary gland, liver, gall bladder

and pancreas.

Urinary/Renal:

Functions: Produces, stores, and eliminates urine; eliminates wastes and regulates volume and

chemical composition of blood; helps regulate production of red blood cells.

Components: Kidneys, ureters, urinary bladder, and urethra

Reproductive:

Functions: Gonads produce gametes (sperm or oocytes) that unite to form a new organism; gonads

also release hormones that regulate reproduction and other body processes

Components: Gonads (testes in males and ovaries in females) and associated organs (e.g. vagina,

mammary glands in females and prostate, penis in males)

Body Cavities:

Major body cavities: Dorsal (back/posterior) and Ventral (front/anterior)

Dorsal cavity is subdivided into:

- Cranial cavity (brain)

- Vertebral/spinal cavity (spine and beginning of spinal nerves)

Ventral cavity is subdivided into:

- Thoracic cavity (organs include lungs, heart, diaphragm)

- Abdominal cavity (e.g. stomach, liver)

- Pelvic cavity (e.g. reproductive organs)

Organic Molecules in the Body:

NOTE: All organic molecules always contain carbon (remember: CHONPS)

Carbohydrates:

Major function: provide energy needed for life

Lipids:

Major types and functions:

- Fatty acids (generate ATP; forms triglycerides

and phospholipids)

- Triglycerides (protection, insulation, energy

storage)

- Phospholipids (cell membrane major

component)

- Steroids (sex hormones, vitamin D, adrenal

hormones)

Proteins:

Nucleic Acids:

Major Function: Stores information used to make proteins

Examples: DNA and RNA

Homeostasis:

Definition: Homeostasis is the condition of equilibrium (balance) in the body’s internal environment

due to the constant interaction of the body’s many regulatory processes.

Importance of Homeostasis:

Homeostasis keeps the internal environment of the body within normal limits in order to prevent

complications such as disease and cancer.

NOTE:

- Homeostasis is a dynamic condition. In response to changing conditions, the body’s

equilibrium can shift among points in a narrow range that is compatible with maintaining

life.

- Internal environment – extracellular fluid (the fluid that surrounds all body’s cells)

- Proper functioning of cells depends on precise regulation of the composition of the

environment surrounding them e.g. temperature, glucose concentration

Homeostasis is mediated by:

- Nervous system (nerves): rapid response, detects changes and sends nerve impulses to

counteract changes

- Endocrine system (hormones): slower response, secretion of hormones into blood

Key components of Feedback Loop/Feedback System:

1. Stimulus (a change in a controlled condition)

2. Receptor: monitors changes from set point/controlled condition

3. Control centre: determines the initial set point range, analyses information from receptors

and determines response (brain or spinal cord)

4. Effector: produces response (with aim to maintain homeostasis)

5. Response: alters the controlled condition

2 Feedback Pathways:

Negative feedback:

- Reverses a change in a controlled condition

- E.g. Temperature regulation, blood glucose regulation, blood pressure regulation

Positive feedback:

- Strengthens a change in a controlled condition

- E.g. Childbirth, blood clotting

Together these feedback pathways help to maintain homeostasis throughout the body’s systems.

Week 2: Cell Structure and Function

Textbook readings: 55-57 (ATP), 63-66, 3.6 (protein synthesis up to transcription page 90), 102

Learning Objectives:

1. List the major organelles within cells and briefly describe their function. (Refer to Learning

Activity Worksheet)

2. Describe the basic structure and function of the plasma membrane.

3. Describe how cells are specialised according to function.

4. Describe simply the main events of protein synthesis.

5. Describe the ATP-ADP cycle.

6. Describe briefly the process of cellular respiration. Distinguish between aerobic and

anaerobic respiration.

NOTE: The cytoplasm is made up of the cytosol, organelles and the nucleus.

Plasma Membrane:

Structure:

The plasma membrane is a flexible yet sturdy barrier that surrounds and contains the cytoplasm of

the cell.

The basic structural framework of the plasma membrane is the lipid bilayer, two back-to-back layers

made up of 3 types of lipid molecules – phospholipids, cholesterol and glycolipids (lipids with

attached carbohydrate groups: NOTE ‘glyco’ = carbohydrate).

NOTE: The bilayer arrangement occurs because the lipids are amphipathic molecules, which means

they have both polar (phosphate head) and non-polar (fatty acid tail: which are hydrocarbon chains)

parts.