Textbook (endocrine and reproduction) - ALL Flashcards
What does the integration centre do?
you suck :3
detects changes from the set point
What parts of the body encompass the integration centre?
- brain
- spinal cord
- endocrine glands
What are antagonistic effectors?
- “push-pull”
- increasing the activity of one effector is accompanied by decreasing the activity of an antagonistic effector
- gives a finer degree of control compared to switching one effector on and off
What is dynamic constancy?
the internal environment is never absolutely constant; homeostasis conditions are stabilized above and below the set point
Homeostasis is ultimately maintained by ____ feedback loops
negative
What are the two categories of regulatory mechanisms that homeostasis is maintained by?
- intrinsic: built into the organs being regulated (nerve fibres innervate organs)
- extrinsic: regulation by nervous/endocrine systems (chemical regulators secreted into blood)
endocrine glands lack ____ that are in exocrine glands
ducts
What are amine hormones?
- hormones derived from tyrosin and tryptophan
- secreted from adrenal medulla, thyroid, pineal glands
what are glycoprotein hormones?
protein bound to 1+ carb groups
What are steroid hormones?
- derived from cholesterol
- secreted from gonads (sex steroids)
- secreted from adreal cortex (corticosteroids + sex steroids)
How do sex and thyroid hormones compare to polypeptide and glycoprotein hormones in the way that they can be taken as medication?
- thyroid and sex can be taken in pill form
- polypeptide and glycoprotein have to be injected to avoid digestion prior to entering the blood
What is a prohormone?
- precursor for polypeptide hormones
- cut and spliced with gland cell to make hormone
What is a prehormone?
- molecule secreted by endocrine gland sometimes inactive in target cells
- target cells modify chemical structure of hormone to activate it (ie: T4 -> T3 to be active)
What is a synergistic hormone effect?
two hormones work together to produce an effect
What is a permissive hormone effect?
hormone enhances target organ responsiveness to second hormone or increases second hormone’s effect
Is there an accumulation of blood hormones? Why or why not?
- No
- hormones are removed and used by target organs or removed by liver if in excess
What are trophic hormones?
- hormones secreted by the anterior pituitary
- high concentrations cause hypertrophy of target organs
- low concentrations cause atrophy of target organs
What is the pars intermedia and what does it do?
- strip of tissue between anterior and posterior pituitary lobes in fetuses (dissapears in adults)
- produces POMC pro-hormone in fetuses
The posterior pituitary stores and releases ____ and ____ that are produced in the hypothalamus
- antidiuretic hormone: stimulates water retention by kidneys
- Oxytocin: roles in partruition and lactaction, rises during ejactulation, heightens trust and understanding of social cues
Posterior pituitary hormones that are produced in the hypothalamus are transported along axons of the ____ tract to posterior pituitary
hypothalamo-hypophyseal
Where are the adrenal glands situated?
cap the superior borders of the kidneys
The adrenal cortex secretes ____ hormones into blood in response to neural innervation
catecholamine (norepinephrine and epinephrine)
What does IGF-2 do?
supports IGF-1 with insulin-like actions
The adrenal cortex does not receive natural innervation, but is stimulated hormonally by ____hormone to secrete ____ from the zona ____ and zona ____
ACTH, cortisol, fasiculata, reticularis
Do IGF-1/2 stimulation lipolysis or decrease glucose utilization?
nah bro
What are somatomedians?
another word for Insluin-like growth factrs (IGFs)
What does parathyroid hormone (PTH) do in terms of regulation of the calcium and phosphate balance.
Kidneys:
- stimulates Ca2+ reabsorbtion and inhibits PO4^3- reabsorbtion
Intestine:
- no direct effect
Bone:
- stimulates reabsorbtion
What does 1,25-dihydroxyvitamin D3 do in terms of regulation of the calcium and phosphate balance.
no u suck. I don’t like this question >:(
Kidneys:
- stimulates reabsorbtion
Intestine:
- stimulates absorbtion
Bone:
- stimulates reabsorbtion
What does Calcitonin do in terms of regulation of the calcium and phosphate balance.
Kidneys:
- inhibits reabsorbtion
Intestine:
- no direct effect
Bone:
- stimulates deposition
What are the three response stages to stress?
- alarm: sympathoadrenal system activated
- resistance: CRH secretion from hypothalamus, ACTH secretion from anterior pituitary, corticosteroid secretion from adrenal (ie: readjustment to stressor)
- exhaustion: if readjustment is not completed, sickness or death may occur
in the thyroid, follicular cells synthesize ____ and parafollicular cells secrete ____
thyroxine ; calcitonin
Androgen-binding protein is secreted into the ____ by ____ to ____
seminiferous tubule lumens ; Sertoli cells ; bind and concentrate testosterone withint the tubules
Describe the negative feedback pathway control of parathyroid hormone (calcium phosphate balance)
- a low amount of Ca2+ in plasma stimulates the parathyroid’s secretion of PTH
- the PTH secreted stimulates bone reabsorbtion
- the PTH also stimulates the kidneys to convert 25-hydroxyvitamine D3 (from the liver) to 1,25-dihydroxyvitamien D3, which results in increased intestinal absorbtion
- When Ca2+ plasma levels increase, it induces negative feedback on the parathyroid to to inhibit further PTH secretion
FSH receptors are only in the ____ in the testes
Sertoli cells