Hormones and Homeostasis

Question 1

What is homeostasis?

Answer 1

maintenance of a constant internal environment e.g body water content, body temp, blood sugar level

Question 2

What is the endocrine system?

Answer 2

like the nervous system but another system that uses proteins (hormones) that are released into the blood stream by glands and target specific cells in the body

Question 3

Describe the endocrine system (speed of action, type of message, method sent, response to message, role in body)

Answer 3

slow (except adrenaline), chemical, via blood (dissolved in plasma), only target cells respond through the message is sent all over body, controls long term processes such as reproduction and growth

Question 4

Describe the nervous system (speed of action, type of message, method sent, response to message, role in body)

Answer 4

fast, electrical impulse, along neurones, message sent directly to a muscle or gland (not all over body), used when a fast response is needed

Question 5

Describe the brain/ pituitary gland(hormone and function)

Answer 5

contains hypothalamus which controls the pituitary gland, ADH -controls amount of water lost in urine

Question 6

Describe the ovary (hormone and function)

Answer 6

produces oestrogen - stimulates uterus lining to develop and growth of secondary female characteristics, progesterone - maintains uterus lining

Question 7

Describe the testis (hormone and function)

Answer 7

produces testosterone - stimulates development of male secondary sexual characteristics

Question 8

Describe the adrenal glands (hormone and function)

Answer 8

produces adrenaline - increases heart rate for fight or flight mode

Question 9

Describe the pancreas (hormone and function)

Answer 9

produces insulin - causes muscles and liver to take up glucose and convert it to glycogen and contra;s level of glucose in blood

Question 10

Describe what happens during high levels of glucose

Answer 10

too much glucose in blood, pancreas produces insulin which enters blood, insulin allows glucose to be absorbed by body cells, blood glucose reduced

Question 11

Describe what happens during low levels of glucose

Answer 11

normal levels of glucose, insulin not produced by the pancreas, less glucose absorbed by body cells, blood glucose remains the same

Question 12

How does the body control blood temperature?

Answer 12

hypothalamus monitors temp of blood and sends signals to the other organs of the body by sweating, shivering or controlling heat loss by controlling the amount of blood flowing near the skin

Question 13

How does the skin control body temp when too cold?

Answer 13

less heat lost
hairs stand on end - hairs traps layer of air and provides insulation
less sweat released - less heat lot via evaporation
vasoconstriction - blood vessels near surface get narrower (constrict), less blood will flow near surface, less heat lost by radiation

Question 14

How does the skin control body temp when too hot?

Answer 14

hairs lie flat - insulating layer of air is not formed
more sweat is released - sweat isn’t cold at is secreted at normal body temp, when sweat evaporates heat energy is taken away rom the skin as evaporation of water requires energy
vasodilation - blood vessels get wider (dilate), more blood will flow near surface and heat lost by radiation