5- Homeostasis And Response Flashcards
Homeostasis
Regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes
- controls
- blood glucose conc
- body temp
- water levels
Thermoregulation
- body temp is monitored and controlled by thermoregulatory centre in the brain
- thermoregularit centre contains receptors sensitive to temp of blood
What happens if body temp is too high
- above 40
- enzymes begin to denature
- digestion, respiration and oter chem reactions in bodies to keep organism alive affected
What happens if body temp too low
- below 35
- enzymes dont work as effecctively
- rate of reaction slower
Body response to body temp too high
- detected by skin temp receptors
- capillaries dilate (vasodilation)
- get bigger
- heat lost through skin s more blood passes through capillaries
- lots of sweat produced
- evaporation causes heat to be lost from skin
- hairs lie flat
Body response to body temp too low
- capillaries constrict (vasoconstriction)
- reduce blood flow, less heat loss through skin
- little/no sweat produced
- hairs pulled erect
- to trap insulating layer of air
- skeletal muscles contract-shiver
- releases heat due to increased respiration in muscle cells
Endocrine system
Made up of endocrene glands which secrete chemicals caled hormones into the blood stream
Hormone
- A chemical messenger produced in an endoxrine gland and is secreted by that gland
- travels in bloood stream to have an effect on another area of the body
Pituitary gland
- found in brain- little ball bit near front
- master gland- control all other glands
- controls growth
- stimulates thyroid, ovaries and testes
Pancreas
- next to stomach
- produces insulin
- control blood glucose
Thyroid
- bow tie in neck
- thyroxine
- controls metabolic rate
Adrenal gland
- above kidney
- adrenaliine
- flight or fight response
- responds to danger/excitement
Ovaries
- oestrogen
- controls menstrual system
- secondray sexual female characteristics
Testes
- testosterone
- controls sperm production
- male secondary sexual characteristcs
Nervous system vs hormones system
- hormoes slower
- hormones last for a long time
- hormones act in a more general way
- nerves act n a v.precise area
Osmoreguation
-kidneys maintaining optimum water and salt conc in blood and body
Ultrafiltration
-kidneys filter the blood under pressure
Why is osmoregulation important
- ensures body can function properly
- eg. Cooling, circulation, excretion