Extra notes (organisation and tissue types)

What is the order of organisation?

Organelle (sub-cellular structure) -> cell (basic unit of all forms of life) -> tissue (group of cells with similar structures and functions working together) -> organ (group of different tissues working together) -> organ system (group of different organs working together) -> organism (group of different organ systems working together)

What are the main organ systems and their functions

Organ system	Organs used	Life processes using it	Function
Respiratory	Lungs + windpipe	Respiration + excretion	Takes in oxygen and excretes carbon dioxide.
Circulatory	Heart + blood vessels	Respiration + growth	Transports substances around the body.
Nervous	Brain + spinal cord	Sensitivity	Collects information and controls the body's response.
Excretory	Kidneys + bladder	Excretion	Filters waste from cells out of the blood, and is stored as urine.
Digestive	Stomach + intestines	Growth  + nutrition	Breaks down food and absorbs the nutrients into the bloodstream.
(Female) Reproductive	Ovaries + womb	Reproduction	Contains the ovaries - where eggs are made - and the womb - where the baby develops.
Musculoskeletal	Muscles + bones	Movement	Protection and support of the body, movement, and production of blood cells.

What is considered excretion?

Breathing out carbon dioxide (a waste product) is excretion, but pooping isn't (because pooping is just getting rid of undigested food - egestion).

What is the function of muscle tissue?

• Contracts for movement, and can conduct electrical impulses

• Some types contract voluntarily (skeletal), whereas others contract involuntarily (smooth and cardiac)

What is the function of glandular tissue?

• Releases hormones and enzymes, and delivers them in the body

• This tissue is rich in capillaries, and each cell must directly contact a capillary in order to deliver the enzyme/hormone to the rest of the body

• An example is the hypothalamus, found at the base of the brain

What is the function of epithelial tissue?

• Covers the whole surface of the body

• Is made up of cells closely packed in one or more layers (which creates a strong, protective barrier, allowing for effective protection, secretion, and absorption), and is specialised to form the covering or lining of both internal and external body surfaces

• Epithelial tissue that occurs on surfaces on the interior of the body is endothelium (e.g. the lining of blood vessels), whereas epithelial tissue occurring on surfaces on the exterior of the body (including surfaces that make contact with the environment that is the body) are called epithelium (e.g. the skin)