Coordination and Response

Nervous system

Organ system consisting of the brain, spinal cord and nurones.

Central nervous system (CNS)

Coordination centre that consists of the brain and spinal chord.

Reflec arc/action

Rapid, automatic, involuntary response to a sensory stimulus.

Stimulus

Change in the surroundings of an organism that produces a response.

Response

Reaction by an organism to a change in it’s surroundings.

Receptor

Cell or organ that detects a stimulus.

Effector

Muscle or gland that brings about a response.

Nerve impulses

Tiny electricle signal that passes along a neurone (nerve cell). Caused by movements of ions in and out the axon.

Synapse

Junction (gap) between two nurones.

Neurotransmitter

Chemical released at the end of a nurone by the arrival of a nerve impulse. Diffuses accross a synapse, causing a new impulse in the following nurone.

Neuromuscular junction

Synapse of a nerve cell on a muscle cell.

Endocrine system

Organ system consisting on glands that secrete hormones into the bloodstream.

Hormone (in animals)

Chemical messenger that travels in the body and has an effect on a target organ or tissue.

Gland

Organ that secretes hormones. Example: pituitary, thyroid, adrenal, pancreas, ovaries, testes.

Adrenaline

Hormone secreted by the adrenal glands that stimulate several organs in the ‘flight or fight’ response.

Testosterone

Male sex hormone made by the testes. Responsible for the development of the male secondary sex characteristics.

Ostrogen

Female sex hormone secreted by the ovaries. Controlls the development of female sex hormones and repair of the unterine lining during the mentstrual cycle.

Progesterone

Female sex hormone made by the corpus lateum in the ovaries, and later by the placenta. Causes further thickening of the uterus lining during the menstural cycle and maintanence of the lining during pregnancy. A drop in progerterone levals stimulates menstruation.

Luteinising hormone (LH)

Hormone produced by the pituitary gland, which stimulates ovulation.

Follicle stimulating hormone (FSH)

Hormone produced by pituitary gland, which stimulates the maturation of eggs in the ovary and sperm production in the testes.

Menstural cycle

Monthy cycle of events preparing a womans utterus for the possible implatation of a fertilised egg.

Ovulation

Release of a mature egg (ovum) from a follicle in the ovary.

Order of the reflex pathway

Stimulus - Receptor - Sensoary Neurone - Relay Nerurone - Motor Neurone - Effector - Response

Label the eye diagram