co-ordination and response

https://qualifications.pearson.com/content/dam/pdf/International%20GCSE/Biology/2017/specification-and-sample-assessments/international-gcse-biology-2017-specification1.pdf

What are the four hormones involved in the menstrual cycle?

What are the four hormones involved in the menstrual cycle?

FSH

LH

Progesterone

oestrogen

Where is FSH made?

pituitary gland

What does FSH do?

Stimulates a few eggs in the ovaries to start maturing in preparation for next period. Stimulates the ovaries. Releases oestrogen.

Where is progesterone produced?

corpus lutem, the follicle case of the matured egg

What does progesterone do?

maintains the endometrium of the uterus, levels fall when mentruation starts, due to unfertilised egg.

Where is oestrogen produced ?

ovaries

What does oestrogen do?

Repairs the uterus lining, and inhibits the pituitary gland from secreting FSH it also stimulates the pituitary gland to secrete LH.

Where is LH produced ?

pituitary gland

What does LH do?

spurs ovulation, the release of eggs from the ovaries

What is your CNS?

central nervous system : brain and spinal cord

What is your PNS?

peripheral nervous system : nerves outside the brain and spinal cord

What is the endocrine system?

the body's chemical communication system; a set of glands that produce and secrete hormones into the bloodstream

Differences between nervous system and endocrine system:

Nervous system
Type of signal : electrical
Speed: very fast
Length of effect: short-term

Endocrine system
Type of signal :chemical
Speed: slow
Length of effect: long- term

Hormones secreted from pancreas?

Insulin

Glucagon

Hormones secreted from Pituitary gland?

ADH LH FSH

Hormones secreted by thyroid gland?

Thyroxine

Hormones secreted by adrenal glands?

Adrenalin

what is the purpose of the mylin sheath ?

allows electrical impulses to transmit quickly.

Relflex arc:

Stimuli - sensory neurone - relay neurone (spinal chord)- motor neurone - effector

When you are looking at an object up close

ciliary muscles contract

suspensory ligaments relax

lens is more convex

When you are looking at a far away object

Suspensory ligaments contract

ciliary muscles relax

lens less concave

function of the conjunctiva

protection and lubrication of the eye

function of the cornea

refracts light

function of the iris

controls how much light enters the pupil

lens

refracts light to focus on the retina

optic nerve

carries impulse between eye and brain

retina

contains light receptors

what happens to your eye in very bright light

The circular muscles contract
The radial muscles relax

The pupil constricts

What happens to your eye in dim light ?

the circular muscles relax
radial muscles contract

pupil dialates

What happens at a synapse?

The electrical impulse arrives at the end of the neuron
The vesicles are stimulated to release neurotransmitters and diffuse across the synapse then bind to receptors on the cell membrane of next neuron and carry the same impulse.

Vasodilation

When your body gets too hot, veins near the skin surface expand (dilate) so more heat energy can escape to the surroundings.

vasoconstriction

when your veins constrict when your cold so that less heat energy can escape to your surroundings.

What are some thermoregulation responses for when the body is hot?

Vasodilation/constriction

perspiration - sweat glands release water which evaporates to cool your skin down

hairs lie flat

What are some thermoregulation responses for when the body is cold?

Vasoconstriction

hairs stand up to create an insulating layer of air around skin surface.

effects of Insulin

If the blood sugar is too high the pancreas releases insulin which increases the glucose absorption in the muscles and liver to convert in to glycogen stores.

effects of glucagon

if the blood glucose levels are too low the pancreas releases glucagon which causes glycogen to break back down into glucose and enter the blood stream.

where is ADH produced

secereted by the pituitary gland

effects of ADH

makes the walls of the collectng ducts impermeable so that more water is reabsorbed into the blood flow and urine is more concentrated of urea (less urine production.)

What is homeostasis ?

maintenance of constant inner conditions eg. water or tempperature

Vitamin D

Helps to absorb calcium, source is oily fish

Vitamin C

Helps to absorb iron, source is citrus fruits, causes scurvy

Vitamin A

needed for vision and growth, source is carrots