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
Menstraul cycle
How long is it approx?
What happens between days
1-4
14
4-14
14-28
28/1
When do girls have their primary follicles(eggs)?
Once puberty starts what happens once a month to one follicle?
What does this release?28days Uterus lining breaks down menstruation Lining of uterus rebuilds Ovulation Lining of uterus maintained Cycle restarts Before they are born Develops into Graafian follicle An egg
Blood glucose What is the stimulus? Where are the receptors located? What is the effector? What is the hormones?
Change in glucose conc
Pancreas
Liver
Insulin or glucagon
Blood glucose
How do we obtain most of our energy?
Which organ can not go without glucose even for a short time? What could it lead to if it does?
What do other cells turn to the use of?
Respire glucose
Brain -> brain damage
Lipids or proteins
Blood glucose
Where do we obtain glucose from?
What is normal blood glucose level?
Breakdown of carbohydrates
Conversion of non carbs
Breaking down glycogen
90mg per 100cm3
Blood glucose
What happens if it is too high?
Pancreas detects
B cells in islet of langerhans release insulin
Insulin
Attached to receptors,active transport cells activated, glucose into cell,increase permeability of memb to glucose
Activate enzymes in cell convert glucose >glycogen
Stimulate the use of glucose in repsiration
Blood glucose
What happens if it’s too low?
Pancreas detects
A cells in islet of langerhans release glucagon
Glucagon
-attaches to receptor sites on cell memb
-activates enzymes convert glycogen>glucose
-stimlates conversion of aa+glycerol>glucose
Glucose passes out of cells into blood
Second messenger model
What is the first messenger model?
What does it bind to to form?
What does this formation activate and what does this result in the production of?
What does this act as?
How does the second messenger produce the required response?
What is the adrenaline response?
Hormone Receptors on cell surface memb,hormone receptor complex Enzyme and chemical Second messenger Causes series of chemical changes Glycogen>glucose
When glucose is not regulated What is hyperglycaemia? This lowers water potential,what does this cause? Which leads to? What are the symptoms of this?
Too high
Lowers water potential which leads to osmotic problems
Dehydration
Thirst,frequent urination,glucose in urine,coma
When glucose is not regulated
What is hypoglycaemia?
What happens to cells?
What are symptoms?
Too low
Deprived of energy
Nausea,loss of concentration,coma
