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Endo Repro 1 > Homeostasis > Flashcards

Homeostasis Flashcards

1
Q

Living orgs must maintain a

Internal enviro composed of

ex

Homeostasis is the dynamic ____ of the internal enviro

A

steady state

physiological variables that fluctuate around a set point

Body temp, blood volume, Bp

constancy

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2
Q

Small changes are _____ taking place ot correct ____ that threaten normal fxn

loss of homeostasis leads to

Input signal sent from, detects

Controller usually is

Purpose

Output signal sent by

Returns variable to

A

constantly, distruptions

dz

sensor/receptor, change

nerve/endocrine cell

evaluate info, initiate a response

effector cells

homeostatic range

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3
Q

Homeostatic values have

achieve steady state over

requires

Homeostasis maintained by

____ variable when too high

_____ variable when too low

Ex

A

set range of physio values

long term

energy

Negative feedback loops

dec

inc

BP

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4
Q

Neg feedback control of BP

occurs via ___

changes in

Mediated by

A

hormone alteration (RAAS)

peripheral vasoconstriction
and urine output (blood volume)

aldosterone from AC

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5
Q

Neg feedback control of glucose

Insulin ___ glucose levels when exceed homeostatic range

Glucagon ____ glucose levels when they fall below homeostatic range

Endocrine signals reach target via (ex)

Neural signals reach target via (ex)

Neuroendocrine combo of _____, ex

these are ____ responses

A

dec

inc

blood (glucose/insluin)

nerves (Knee jerk reflex)

neural/endocrine (hypothalamic AP axis)

distant

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6
Q

Local responses

Paracrine signals reach

Autocrine signals affect

Signals can act at

such as

A

neighboring cells via ISF

cell generating the signal

multuple levels

cortisol- affects cell it is made in, nearby cells, distant targets

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7
Q

Feedforward regulation is

No ____ required

_____ response

Minimizes

Ex

A

anticipatory (proactive)

deviation

accelerates

fluctuation

circadian rhythms, salivation

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8
Q

Neg feedback is a ____ reflex

Feedforward regulation ___ speed of homeostatic response

Positive feedback ___ signal

Not a

Requires ____ to terminate

example

A

homeostatic

increases

amplifies

homeostatic control mech

external factor

parturition

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9
Q

Endocrine system fxn unit

chemical messenger

mode of transmission

Rxn time

A

gland cell

hormone

circulation

Min- day

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10
Q

General fxn of hormone

maintain ___ of internal enviro

adapt to changes in

control processes involving multiple tissues such as

A

internal environment

external enviro (food availability, response to stress)

Ion/fluids, energy metabolism, digestion, growth, repro

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11
Q

Hormones are secreted by

released into

Regulate, do not ___, fxn in

Exert effects at

Regulate things such as

At molecular level, can inflence

A

specific cells

bloodstream in small amounts

initiate, target cells

cellular level

cell division, differentiation, ativation, motility, secretion

gene trxn, protein synthesis, enzyme activity, protein interactions

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12
Q

Chemical signalling types

a single gland can

hormones can be produced by

types of hormones

A

autocrine, paracrine (AC), endocrine, Neuroendocrine (hypothalamic hormones regulating AP)

secrete multiple hormones (AP)

more than 1 gland (somatostatin)

Tyrosine derivative, steroids, proteins, peptide

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13
Q

Tyrosine derivatives

catecholamines produced by adrenal medulla and CNS

iodothyronines produced by thyroid gland

A

DA, NE, Epi

T3, T4

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14
Q

Steroid hormones

AC- A, C, A

Gonads T, E, P

Placenta P, E

Kidney, C (aka)

A

Aldo, Cortisol, Androstenedione

Testosterone, Estradiol, Progesterone

Progesterone, Estrogens

Calcitriol (VD3)

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15
Q

Characteristics of Steroid hormones

derived from

water _____, transported in blood when

____, so cross membranes

Receptors located

Gland storage ____, bc

can be administered

A

cholesterol

insolubule, bound to protein

lipophilic, easily

IC

minimal, diffuse easily out of cells

orally

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16
Q

Protein hormones

Hypothalamic releasing G, C

AP

Pancreatic islet hormones

P____
C_____
Placental, such as

A

GHRH, CRH

Glycoproteins (alpha/beta subunits, beta for specificity)- LH/FSH/TSH
GH, PRL, ACTH

insulin, glucagon

PTH
Calcitonin

hCG

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17
Q

Peptide hormones

Hypothalamic releasing/inhibit hormones G, T, S, G

Posterior pituitary hormones O, A

Others

A

GnRH, TRH, Somatostatin, GHIH

Oxytocin, ADH

Angiotensin, MSH

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18
Q

Characteristics of peptide/protein hormones

Synthesized on, as

Stored inside cells in

Often circulate

relatively

Receptors are

Cannot be administered, bc

A

ribosomes, prehormones/pre-prohormones

membrane bound granules

unbound

polar

EC

orally, digested

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19
Q

Protein/peptide hormones life cycle

Trxn/processed in

TRxn factors bind to

Processing can occur

Processed mRNA enters

A

nuclues

DNA at specific sequences encoding a hormone

post transcriptional

cytoplasm

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20
Q

Processing of peptide/proteins occurs in, stored in

stage, mRNA in ribosomes binds peptide chain, directed to lumen by

enzyms in ER chop off _____, creating

prohormone goes through ER to _____, where ___ occurs

Secretory vesicles then bud off _____, enzymes cleave _____ into active _____

when signal for release occurs, secretory vesicles relase via ___, itno

hormone then goes to

A

ER/Golgi, secretory vesicles

(preprohormone),signal sequence

signal sequence, inactive prohormone

Golgi, final processing/glycoslyation

Golgi, promhormone, hormone

exocytosis, EC space

target

21
Q

Life cycle of steroid hormone

Synthesized via

Rate limiting enzyme is, converts ____ to pregnenolone

Similarity of structures leads to

defect in one enzyme can result in

A

cholesterol, special enzymes

side chain cleavage enzyme (P450), cholesterol

cross reactivity at pharm levels

dramatically altererd hormone products

22
Q

Hormone life cycle

Secretion for Proteins/Peptide
Steroids/Thyroid

Transport of catecholamines/proteins/peptides

exception is, transpoted when boudn to

Steroid/thyroid hormones are ____, circulate when

Only ____ portion is biologically active

A

Exocytosis
Diffusion

Free/unbound (hydrophilic)

GH/IGF, proteins

lipophilic, binding proteins

free

23
Q

Binding proteins synthesized and sec by, circulate in

binding affinity of these proteins is ____ than albumin, rendering

concentration of bound hormone, free hormone, binding protein exist in

dec in free hormone results in

bound hormone serves as ___ of readily avaliable hormone

bound hormone is not ____ for metabolism, thus binding protein _____ hormone’s half life

A

Liver (CBG, TBG, SSBG), plasma

equilibrium

release of bound hormone from binding protein

pool

available, inc

24
Q

Inc in binding protein in pregnancy due to

results in ____ bound hormone

briefly ____ amount of free hormone

rapidly returns via, resulting in

A

elevated estradiol levels

inc

dec

NFM, no net change

25
Q

Chronic inc of plasma binding protein

____ in bound/total hormone

no change in _____ bc of

most assays measure ____ hormone level

A

inc

free, NFM

total

26
Q

Receptors have ____ binding sites for homones

this confers _____ as many hormones circulate in blood

Protein/peptide hormone receptors are, bound to

Protein/peptide hormones transmit signal via

Signal transduction pathway

A

high affinity

specificity

EC, CM

signal pathway

hormone binds, induces conf change

release IC 2nd messenger

activates effector proteins, resulting in action

27
Q

Signalling pathways

___ steps

amplyify _____

activate multiple pathways of multiple cell fxns from

Rapid action s in

slower actions in

antagonism by

A

multiple

initial hormone/receptor binding

one hormone bidning event

cytoplasm

nucleus

constitutive and regulated NFM

28
Q

IC messengers

cyclic nucleotides such as, bind to

released from

Ions that lead to

Lipid messengers
DAG, which activates
IP3 to inc
both come from

A

cAMP, effector kinases (PKA/ion channels)

AC/GC actication

direct/indirect regulation of effector proteins

PKC
IC Ca
Phospholipase C

29
Q

GPCR (protein hormone receptor)

Gs stimulates

Gi inhibits

Gq activates

can affect

result in release of

A

AC

AC

Phospholiapse C

ion channels, enzyme activity, trxn

PTH, LH, FSH, TSH, ACTH

30
Q

Protein hormne receptors can

Activate enzymes such as

Tyrosine Kinases
GF subtype
Cytokine subtype

Other type

A

gate channels (affect Ca)

kinases/phosphatases

receptor is tyrosine kinase

receptor associated with kinase (JAK)

serine/threonine

31
Q

Steroid receptors are

___ acting than protein hormones, bc

can be found on ____ for rapid actions

structure included in

Steroid receptors on ER/PR/GR/MR/AR suttle bw

Thyroid/VD3/RA/PPAR are ___ bound

in absence of hormone

A

IC, act as Trxn factors

slower, action utilizes trxn/trsn

PM

nuclear receptors- bind DNA

cytoplasm/nucleus

nucleus to reponse elements

gene trxn is inhibitied

32
Q

Action of steroid receptors

Hormone receptor complex binds to

can activate/dec trxn by

A

specific DNA sequence called the hormone response element to alter trxn

recruiting coactivators/corepressors

33
Q

At the receptor, hormones inactivated via

in plasma

in kidney

Half life is ____ correlated with metabolic clearance rate

A

enzyme degredation, dec conc of Ca, confomrational change in receptor, endocytosis

enzyme degradation in blood/liver/kidney

excreted

negatively

34
Q

Hypothalamic pituitary axis works via

Estradiol induction of preovulatory gonadotropin surges works via

A

Neg feedback

Pos feedback

35
Q

Hormone action

change in response via

down regulation leads to

up regulation leads t

changes in sensitivity vua

dec in sensitivity shifts DRC to

changes can be, ie they can affect own/other hormone receptors

A

receptor number

dec receptor number (result of high levels of hormone), downward shift of curve

inc receptor number, inc shift of DRC

receptor affinity

right (more hormone required for response)

homologous, heterologous

36
Q

Endogenous parameters affecting hormone conc

Most hormones manifest

can be

serum binding proteins an alter

A

multiple superimposed rhythms on secetory pattern

diurnal, ultradian(pulsatile), responsive

total hormone conc

37
Q

Exogenous parameters affecting hormone conc

act via

Circadian rhythms

rhythm occurs over even in constant conditions

Normal period is

Stress elevates blood levels, changing feedback set point to

effect is superimposed on

level of hormone is ______, but does not effect ______

A

CNS

24 hrs

24 hr

HPA

hormone release pattern

inc, pattern of release

38
Q

Neuroendocrinology is the interaction bw

pituitary gland is the master bc

structure includes

A

nervous/endocrine systems

has so many endocrine reflexes

anterior, endocrine lobe and posterior, neural lobe

39
Q

PP is ___ tissue

Comprised of ____ of the peptidergic neurosecretory neurons in the

innervation is direct via ______

comosed of axons of ____ nucleus

project down the ____ and terminate in ____

___ and ____ hormones

receives direct ____ bloody supply

releases hormones into

A

axons/terminals, hypothalamus

hypothalamohypophyseal tract

supraoptic and paraventricular

pituitary stalk, PP

store/release (no synthesis)

arterial

systemic circ

40
Q

Hormones of PP

ADH released in response to

Oxtyocin released in response to

released into systemic circ via the

targets are

detectable in

A

hypothalamic osmoreceptors and CV volume receptors

neural afferent input triggered by stretch of cervix at parturition, suckling of mammary glands

venous drainage of PP

distant

peripheral blood

41
Q

AP hormones

Glycoproteins

beta is

GH/prolactin family

POMC Family

POMC is the _____

cleaved to become

released w

skin melanocytes cleave ACTH into

A

TSH, FSH, LH (alpha/beta subunits)

unique

GH, prolactin

prohormone

ACTH/ gamma lipotropin/ B endodorhin in anterior lobe

aCTH

A MSH (very similar to ACTH)

42
Q

AP is glandular tissue

N ____ innervation, ______ blood supply

hormone release controlled by

released at terminals near _____ in the median eminence at top of pituitary stalk

transported to AP via

Diffuse from secondary capillary plexus in AP to

HH are ____ detectable in peripheral blood

A

direct, arterial

HR and IH

primary capillary plexus

stalk portal capillaries

target cells

not

43
Q

If pituitary stalk is cut, bc no other blood supply

AP hormones will

Prolactin (normally under chronic negative control) will

if AP is transplanted and revascularizes what happens

LH, FSH, TSH, GH, ACTH
PRL

AP gland is under constant

A

dec in blood

inc until cells die/necrose frome lack of blood

dec
Inc

negative feedback control

44
Q

Panhypopituitarism leads to

caused by

can be

if complete, plasma levels of hormones are

HR hormone synthesis/sec will ___ due to lack of

still will not be detected in

A

loss of all AP fxn

destroyed gland- hemorrhage/adenoma

partial/complete

undetectable

inc, negative feedback

peripheral blood

45
Q

Isolated PH deficiency

loss of ____ hormone fxn

Kallmans syndrome

leads to

A

one

GnRH neurons do not migrate from olfactory placode early in life

absence of GnRH, dec LH, FSH, hypogonadism, anosmia

46
Q

Sheehans syndrome results from

portal capillaries operate at ____, thus are susceptible to low blood pressure

Plasma levels of AP hormones will ____ due to

Prolactin would initially ______, and eventually dec as cells die

PP hormone levels would be ___ bc there is

A

postpartum hemorrhage

low pressure, clotting/infarct/shock

dec, loss blood supply of pars disalis

inc

unaffected, direct arterial blood supply

47
Q

Pituitary gland found in, below, connected to brain via

tumors can compress OC leading to

Whiplash injuries sever

complete stalk severing leads to

Also leads to

Lose

A

Sella turcica, optic chiasm, pituitary stalk

HA/bilateral hemaniopsia

stalk

dec blood supply to AP- necrosis (no AP fxn- hypopituitarism)

lost fxn of PP

Oxytocin (asx), ADH (DI)

48
Q

Tumors of somatotrophes (excess GH)

Tumors of lactotrophes (excess prolactn)

Tumors of corticotrophes (excess ACTH)

Tumors of thyrotropes (Excess TSH)

Tumors of gonadotropes (excess of gonadotropins)

Tumor inc target hormone (inc Neg feedback, dec HR hormone syn)

A

Acromegaly/gigantism

infertility, galatorrhea

Pituitary Cushing’s (hypercortisol)

Hyperthyroidism

in kids, precocious puberty

tumors dont respond to negative feedback or dec in HRH

Endo Repro 1 (24 decks)

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