Levels of Organisation

What are the levels of organisation?

1. Chemical or molecular

2. Cellular

3. Tissue

4. Organ

5. Organ System

What is chemical or molecular level?

Atoms such as hydrogen, carbon, oxygen and nitrogen and molecules such as water, sugars, fatty acids, amino acids and nucleotides

What is the cellular level?

Cells are the smallest unit of life, cellular differentiation can take place so cells are specialised for different function in higher life forms

What is tissue level?

Cells that secrete and regulate extracellular material and fluids combine to form tissues with special functions

What is organ level?

A discrete collection of two or more tissues cooperatively performing a function. Tissues combine to form organs with multiple functions

What is organ system level?

Organs interact in organ systems

What are some examples of cells?

• Cells lining intestinal tract

• Smooth muscle cell

• Neuron in brain

What do epithelia do?

Tissues that cover exposed surfaces, line internal passageways and chambers, and produce glandular secretions

What do connective tissues do?

They fill internal spaces, provide structural support, and store energy

What are some examples of organs?

• Heart

• Femur

• Biceps brachii muscle

What are the 11 body system?

• Integumentary

• Skeletal

• Muscular

• Nervous

• Endocrine

• Cardiovascular

• Lymphatic

• Respiratory

• Digestive

• Urinary

• Reproductive

What are the key functions of the integumentary system?

Protection, thermoregulation, sensation

What is the key function of the skeletal system?

Protection

What is the key function of the muscular system?

Allows movement

What is the key function of the nervous system?

Communication

What is the key function of the endocrine system?

Allows communication and coordination through hormones

What is the key function of the cardiovascular system?

Transport gases and nutrients as well as waste

What is the key function of the lymphatic system?

Defence against pathogens (involved in the immune response)

What is the key function of the respiratory system?

Ventilation

What is the key function of the digestive system?

Takes nutrients into the body

What is the key function of the urinary system?

Removes waste from the body

What is the key function of the reproductive system?

Reproduction

What does the integumentary system look like?

What does the skeletal system look like?

What does the muscular system look like?

What does the nervous system look like?

What does the endocrine system look like?

What does the cardiovascular system look like?

What does the lymphatic system look like?

What does the respiratory system look like?

What does the digestive system look like?

What does the urinary system look like?

What do the reproductive systems look like?

What is homeostasis?

The maintenance of a constant internal environment

What is negative feedback?

Opposes variations from normal. For example, thermoregulation (stimulus → receptor → control centre → effector → response)

What is positive feedback?

Exaggerates variations. For example, blood clotting