Homeostasis Flashcards
Thermoregulation
What are the two groups of animals that can keep their core body temp constant irrespective of the external environment?
What is are these described as? Aka?
What is the opposite of this? Aka?
Mammals and birds
Endotherms aka regulators
Ectotherms aka conformers
Regulation of body temp in exotherms
Why can they not warm up by exercising?
What do they do to cool down?
What do they do to warm up?
Requires respiration
Low body temp=slow resp
Hide in the shade
Light coloured reflect sun
Expose themselves to the sun
Dark skin absorbs heat
Generate metabolic heat which provides a proportion of body heat
Gain warmth from the ground by push their body to the ground raise up when required temp reached
What is osmoregulation?
Control of water and ions
Hypothalamus Where is it found? What does it measure? What does it do? What do its 2 centres regulate? Where does it gather its information from? What does it compare its info to? What does it do then?
Pituitary gland at the base of the brain
Temperature
Heat loss and heat gain
Directly from passing blood and from receptors in skin
The body thermostat
Initiates action of effectors to bring core temp back to normal value
What are the physical ways of dealing with heat?
What are the chemical ways?
Hairs lie flat and vasodilation
Sweating and metabolic rate slows down
Explain how :
Hairs lying flat
Vasodilation
works.
Less space,less air trapped, easier to lose heat
Arteriolar to skin dilate,shunt vessels closed off increased blood flow to skin, more heat loss
Explain how
Sweating
Metabolic rate slowing down
works.
Sweating salty solution from sweat gland, evaporated off skin, cools down
Less heat generated by body
What are the physiological ways of warming up?
What are the physiological ways of cooling down?
Hairs lay flat
Vasodilation
Sweating
Slowing down metabolic rate
Vasoconstriction
Piloerection
Increased metabolic rate
Shivering
What is homeostasis?
What has to be kept constant?
Maintaining a constant internal environment
pH,temp,water
Negative feedback
What are the four hormones of the menstraul cycle?
Which 2 are proteins and which 2 are steroid?
FSH oestrogen LH progesterone
FSH, LH proteins oestrogen,progesterone steroids
FSH
Where is it produced?
What does it stimulate?
Pituitary gland
Development of the follicles
Oestrogen Where is it produced? What does it do to the uterus lining? What does it stimulate? What does it inhibit?
Ovaries in Graafian follicles
Rebuilds it
Development of endothetrium and LH to be released from pituitary gland
FSH
LH Where is it produced? What does it bring about? What does it stimulate? What does it do to the Graafian follicle?
Pituitary gland
Ovulation
Corpus luteum therefore production of progesterone
Graafian follicle > corpus luteum
Progesterone
Where is it released?
What does it maintain?
What does it inhibit?
Ovaries corpus luteum
Lining of the uterus
LH and FSH
Sequence of negative feedback with FSH,oestrogen,LH,progesterone?
FSH stimulates the production of oestrogen
Oestrogen levels rise slowly inhibiting FSH production and as a result lowering oestrogen levels
The rapid rise in oestrogen just before ovulation stimulates FSH
FSH boosts follicle development before ovulation
This leads to an increase in oestrogen
Which stimulates LH production
LH stimulates he release of progesterone which inhibits LH +FSH
reduction in LH causes a reduction in progesterone
Reduction in progesterone causes an increase in FSH