homeostasis Flashcards
what is the importance of maintaining homeostasis
- maintaining an internal set of conditions
- keeping enzymes happy
nervous system: NTM balance to regulating cognition, mood, behaviour. Synaptic transmission; regulation of ntm release, receptor strenth.
excretory system: remove waste, avoid buildup, maintain bp and concentration of electrolytes, produce and release hormones (renin) properly
vant hoffs rule
- for every 1- degrees, the reaction rate doubles twice as much product
- increased particle collisions, increased reaction rate, increased activity
catabolism vs anabolism
catabolism- breaking apart
anabolism- putting together
3D shape of enzymes/protein
- composed of amino acids with a specific sequence
- amino acids are put in a certain order based on genes
- likes dissolve likes, electrostatic forces, disulphide bridges
essentially, a disease is
enzyme/pathway isn’t functioning properly
how much energy are animals using from food to maintain a set of internal conditions
- around 60%, internal regulation is expensive
- homeostasis keeping cells happy is not linear, contains upper and lower thresholds
the number of calories you need is essentially the amount of energy you need for
homeostasis, taking in fewer calories causes the body to use glycogen storage, fats, and proteins for calories
feedback loops
negative: (thermostat concept)
- works against changes
- maintains dynamic equilibrium
- trying to maintain a moving balance (nonlinear)
UPPER LIMITS: cool body off
LOWER LIMITS: warm body up
positive: reinforce changes by amplifying an effect
- if you were warm, your furnace would stay
Ex. Increased virus distribution, increased infected people
order of a feedback loop
stimulus
sensor
control
effector
why do we breathe faster when we exercise
negative f.l.
- co2 and blood pH, CO2 reacts with H2O in the blood to form a weak acid, lowering blood pH
STIMULUS: increased co2/drop in pH
SENSOR: medulla oblongata has sensory cells
CONTROL CENTRE: medulla is also the control centre
EFFECTOR: cause of change-diaphragm and the heart
how do cells know when to act
- P. f.l: oxytocin for birth, blood clotting
- hormones (chemical signals that influence cell activity)
- produced by glands, travel through the circ system, affects cells with matching receptors
Baby moving towards cervix (positive feedback loop)
Dehydration (negative feedback loop)
CERVIX
- stimulus: tension in the cervical tissue
- sensor: stretch receptors are stimulated
- control centre: hypothalamus stimulates posterior pituitary to release oxytocin
- effector: smooth muscle in uterus wall contracts
DEHYDRATION
stimulus: drop in BP
sensor: –
control centre: hypothalamus and pituitary glands (releasing antidiuretic hormone=preventing urination)
effector: increased blood pressure, because the lack of urination increases blood volume
what are hormones
- chemical signals that influence cell activity
- produced by glands, travel through the circ system, affects cells with matching receptors
what are endocrine glands (examples)
kidneys- release urine
lacromo glands- produce tears
salivary glands- produce salivia
mucus glands- produce mucus
function of thyroid glands
function of parathyroid glands
- regulate metabolism
- control calcium in the blood
infundibulum
tissue that connects hypothalamus to pituitary gland
hypothalamus and pituitary gland
hypothalamus:
- coordinator of homeostasis
- produces releasing hormones, sent to pituitary gland
pituitary gland:
- found below the hypothalamus in the brain
- controls growth and water levels in the blood
- produces stimulating hormones sent throughout the body
pituitary tube: causes abnormal growth
hypothyroidism: less thyroid circulating through body for cell respiration: decreased atp, decreased energy
therefore, hyperthyroidism can cause hair loss
Which messenger(s) is/are used to regulate meiosis and helps with oogenesis and spermatogenesis
FSH, LH
which messenger deals with melatonin?
which messenger encourages growth?
which messengers causes milk to be produced?
(both directly work on tissues)
melatonin: MSH
Growth: GH
prolactin: causes milk to be produced
posterior pituitary is involved in releasing which hormone
oxytocin: acts directly on all smooth muscle (all muscle not attached to bone)
to cause contractions
releasing hormones causes
stimulation of other glands to produce hormones
- allows glands to communicate with one another
- are used in temperature regulation
EX. COLD EXPOSURE
- COLD EXPOSURE
- HYPOTHALAMUS (releases TRH (thyroid reset hormones))
- PITUITARY (releases TSH)
- THYROID
- THYROXINE
steroid vs peptide hormones
steroid:
- go right into the cell. receptor is in the cytoplasm,
- bind with receptors in the cytoplasm
- hormone: receptors complex enters the SINGLE BAND nucleus and creates proteins via protein synthesis
steroid—cholesterol—lipid
(non polar in nature, can diffuse through the phospholipid bilayer)
peptide:
- receptors are on the outside of the cell membrane
- will bind with their receptors
- doesn’t go into cell
- causes a transduction pathway (domino effect)
- too large to cross through the membrane (proteins) goes and causes a change
- SECOND MESSENGER PRODUCED: reduced version of ATP- cAMP
- cAMP activates protein kinases: enzymes that regulate protein activity