Human Biology ATAR Year 11 - Unit 1

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CELLS AND TISSUES

What is the human body comprised of?

Cells, tissues and organs within complex systems which work together to maintain life.

*What is a cell organelle?

A small structure in a cell that is surrounded by a membrane and has a specific function.

What is the function of cell organelles?

They maintain life processes and require:

- input of materials

- removal of wastes

to support the efficient functioning of the cell

What is the function of the cell membrane?

It seperates the interior of the cell from its outside environment.

It allows for movement of meterials into and out of the cell.

*by osmosis, simple diffusion, facilitated diffusion, active transport and vesicular transport (endocytosis/exocytosis)

What are factors affecting the exchange of materials across the cell membrane?

- Surface area to volume ratio

- Concentration gradients

- Physical & chemical natre of materials being exchanged

What can the various tissues of the human body be categorised as?

- Connective

- Muscular

- Nervous

- Epithlial

METABOLISM

What are controlled in the prescense of specific enzymes?

*Biochemical processes, including anabolic and catabolic reactions in the cell.

Where does cellular respiration occur?

In different locations of the:

- Cytosol

- Mitochondria

*to catabolise organic compounds, aerobically or anaerobically, to store energy in the form of adenosine triphosphate (ATP)

What is required for efficient metabolism?

Cells require:

- Oxygen

- Nutrients

- Carbohydrates

- Lipids

- Proteins

- Vitamins

- Minerals

What can enzyme function be affected by?

- pH

- Temperature

- *Presence of inhibitors

- *Co-enzymes & Co-factors

- Concentration of reactants & their products

RESPIRATORY SYSTEM

What is the function of the respiratory system?

The exchange of gases between internal and external environments of the body at the cell, tissue and organ levels.

How is the efficient echange of gases in the lungs maintained?

- Breathing

- Blood flow

- Structure of alveoli

CIRCULATORY SYSTEM

What is the function of the circulatory system?

Transport materials within the internal environment.

-Carry oxygen

- Nutrients

- Hormones to cells

- Remove waste products (e.g. carbon dioxide)

What do the components of blood do in the circulatory system?

- Transport of different materials around the body (plasma & *erythrocytes)

- Play a role in clotting blood (*platelets)

- Protection of the body (*leucocytes)

What is the function of the Lympathic System?

- Return tissue fluid to the circulatory system

- Assist from protecting the body from disease

Steps of blood clotting in the case of a broken blood vessel

- vasoconstriction to reduce flow and minimise blood loss

- primary hemostasis (formation of a platelet plug)

- secondary hemostasis (clotting factors released to make stronger plug)

- clot stabilisation (makes a fibrin clot)

- fibrinolysis (clot is dissolved as cells replace broken tissue)

DIGESTIVE SYSTEM

What is the function of digestive system?

To supply nutrients in a form that can be used in cells.

What does digestion involve?

- The breakdown of lagre molecules to smaller ones by mechanical digestion (*teeth, peristalisis, churning and bile)

- Chemical digestion (enzymmes with specific operatin confitions and functions are loccated in different sections in the digestive system)

What parts of the body aid the process of digestion and how?

- Salivary glands

- Pancreas

- Liver

- Gall bladder

All of these produce secretions which help aid the process of digestion.

What does absorption require?

Requires nutrients to be in a form that can cross cell membranes into the blood *or lymph and occurs at different locations, including the small intestine and large intestine

What does elimination do?

It removes undigested materials and some metabolic wates from the body.

EXCRETORY SYSTEM

What is the function of the extcretory system?

It regulates the chemical composition of body fluids

- This is done by removing metabolic wastes and regulating water, salts and nutrients (regulatory processes not required)

What does the deamination (removing an amino group from a molecule) of amino acids in the liver do?

It produces urea (chemical waste product) which is then transported to the kidneys for removal.

What do the nephrons in the kidney assist in?

- Filtration

- Absorption

- Secretion during urine formation to maintain composition of bodily fluids (hormne control not required)

What is a nephron?

Filtering units of the kidneys.