Hormones Flashcards
What is a hormone?
A chemical substance secreted by the endocrine glandand travel through the bloodstream to alter activities in the target organs.
What happens in the pancreas?
It makes insulin and glucagon. The insulin lowers the blood glucose concentration. Glucagon increases it.
Explain Adrenaline
The adrenal gland secretes it when one is frightened or angry, helping the body cope with an emergency. It usually increases heart rate, breathing rate and widens pupils to allow light in.
Adrenaline in relation to the liver
To create energy adrenaline stimulates liver cells to convert glycogen to glucose, which diffuses into the blood. This increases the concentration of glucose in the blood, so that there is more available to the muscle contraction for action.
Features of the nervous system
Nervous system:
-structure; nerves
-forms of information; electrical impulses
-speed; fast
-longevity of action; short-lived
-targer area; at the end of a neurone
-reponse; muscles contract
Features of the endocrine system
-structure; secretory cells in glands
-forms of information; hormones (chemicals)
-pathways; blood
-speed of information; slow
-longevity of action; slow&longer lasting
-target area; whole tissue /organ
-response; conversion of glucose to glycogen, protein synthesis, rate of respiration
Define homeostasis
The maintenance of constant internal conditions in the body, so that enzymes control metabolism efficiently
Controlling the body’s temperature
The normal temp for humans is 37⁰, therefore if warner blood reaches the Brain an impulse is sent along the nerves to the skin to promote heat loss e.g our sweat glands produce sweat and this helps us cool down so the body returns back to normal
Explain the function of the hormone insulin
Insulin stimulates the liver cells to convert glucose into the storage compound GLYCOGEN. This stimulates the liver cells to absorb lots of glucose from the blood so the concentration decreases and returns back to normal
