quiz 1 Flashcards
1
Q
5 mechanisms of intercellular activity
A
direct communication, paracrine communication, autocrine communication, endocrine communication, synaptic communication
2
Q
direct communication
A
through gap junctions
chemical signals are from ions, small solutes, lipid soluble materials
limited to adjacent cells of the same type that are interconnected by connections
3
Q
paracrine communication
A
through extracellular fluid
chemical signals from paracrine (one cell to another cell)
limited to the local area and target cells must have appropriate receptors
4
Q
autocrine communication
A
through extracellular fluid
chemical signals from autocrines released to itself
limited to the cell that secretes the chemical signals
5
Q
endocrine communication
A
through the blood stream
can arise from tissues and travel far
6
Q
synaptic communication
A
across synapses
chemical signals from neurotransmitters
limited to very specific areas
7
Q
similarities between nervous system and endocrine system
A
- rely on release of chemicals that bind to specific receptors on target cells
- share many chemical messengers; NE and E are hormones when realeased into bloodstream but actually are neurotransmitters when released across sysnapses
- regulated by negative feedback controls
- share common goal: to preserve homeostasis by coordinating and regulating actives of cells, tissues, organs, systems
8
Q
hormones, paracrine, and autocrines can be divided into 3 groups based on their chemical structure. what are 3 groups
A
hormones: chemical mean of messaging inside bodies of all multicellular organisms
paracrine: hormones that communicate between closely related neighboring cells
autocrines: action of hormones on themselves
1) amino acid derivatives
2) peptide hormones
3) lipid derivatives
9
Q
amino acid derivatives
A
- thyroid hormones produced by thyroid gland
- catecholamines which are compounds of epinephrine, norepinephrine, and dopamine
- trytophan derivatives, melatonin (secreted by pineal gland)
10
Q
peptide hormones
A
- includes most hormones of the body
- hormones secreted by hypothalamus, thymus, digestive tract, pancreas, pituitary glands
- glycoproteins (polypeptides that have carbohydrate side chains) TSH LH FSH
- synthesizes as inactive hormones (pro hormones) that are then activated before or after release
11
Q
lipid derivatives
A
-eicosanoids (carbon ring with fatty acids side chains)
they are important pacacrine factors that coordinate cellular activities in extracellular fluids (blood clotting)
examples
lukotrienes: secondary roles as hormones
prostglandins: involved in primarily coordinating local cellular activities
-steorid hormones : cholesterol base released by: -reproductive organs (androgens, estrogen, progesterone) -adrenal cortex (corticosteroids) -kidneys (calcitrol)
12
Q
what happens if a target cell doesnt have the appropriate hormone receptor
A
the circulating hormone has no effect
13
Q
hormone receptors are located where
A
on plasma membrane (extracellular factors) or within target cells (intracellular factors)
14
Q
receptor in plasma membrane
A
- receptors for catecholamines (E, NE, dopamine) peptide hormones, and most eicosonoids
- these are water soluble hormones that cannot cross plasma membrane
- hormone acts as first messenger relaying message to second messenger
- second messenger then affects enzyme activity to exert the hormones effects on the cell and change cellular metabolic reactions
15
Q
important second messengers
A
cyclic AMP (cAMP) derivative of ATP calcium ions (Ca2+)
16
Q
receptor in cytoplasm or nucleus (steroids)
A
- steroid hormones diffuse across the lipid part of the plasma membrane and bind to intracellular receptors in cytoplasm or nucleus
- steprids affect DNA transcription rate and protein synthesis
- steroids change synthesis of enzyme and structural proteins affecting cells metabolic activity
17
Q
receptor in cytoplasm or nucleus (thyroid hormones)
A
- thyroid hormones are primarily transported across plasma membrane by carrier mediated processes
- bind to receptors on mitochondria affecting energy production
- bind to receptors in nucleus, affecting cells metabolic activity
18
Q
hypothalamus control
A
- contains both brain centers and endocrine tissues
- provides the highest level of control by integrating nervous and endocrine systems through 3 mechanisms
19
Q
what are 3 mechanisms of hypothalamus control
A
1) has neurons that secrete two hormones released from posterior pituitary
- ADH and OXT
2) secretes regulatory hormones that control anterior pituitary gland endocrine cells
- transported to pituitary through hypopheaseal portal system
- has releasing hormones (stimulate hormone realize at anterior lobe of pituitary)
- has inhibiting hormones (prevent hormone release at anterior pituitary)
3) contains autonomic (sympathetic) neurons that stimulate release of hormones from adrenal medulla
20
Q
another name for anterior lobe of pituitary
A
adenohypophysis
21
Q
another name for posterior love of pituitary
A
neurohypophysis
22
Q
how many hormones from anterior and posterior pitutitary
A
anterior pituitary
- 7 peptide hormones that are called tropic hormones because they turn on other endocrine glands
posterior pituitary
-2 peptide hormones
all 9 bind to membrane receptors and use cAMP as 2nd messenger
23
Q
thyroid stimulating hormone (TSH)
A
anterior pituitary
target: thyroid gland
- triggers release of thyroid hormones
- released in response to thyrotropin releasing hormone (TRH) from hypothalalmus
- TSH and TRH decreases release when thyroid hormone levels rise (negative feedback loop)
24
Q
adrenocorticotropic hormone (ACTH)
A
anterior pituitary
target: adrenal gland
- stimulates release of steroid hormones from adrenal cortex ( specifically those that affect glucose metabolism
- released in response to corticotropin releasing hormone (CRH) from hypothalamus
25
gonadtropins 2 types
- regulate gonadal (testes and ovaries) activites
- released in response to gonadatropin releasing hormone (GnRH) from hypothalamus
- FSH and LH
26
Follicle stimulating hormone (FSH)
anterior pituitary
- females: promotes ovarian follicle development and (in cohort with LH) stimulates secretion of estrogen
males: promotes maturation of sperm
- inhibited by inhibin (peptide released by gonads)
27
Luteinizing hormone (LH)
anterior pituitary
- females: induces ovulation and promotes secretion of estrogens and progesterone which prepares body for pregnancy
- males: stimulates production of sex hormones (androgens), primarily testosterone
28
Growth hormone (GH)
anterior pituitary
target: musclloskeltal system
- stimulates cell growth and reproduction by stimulating rate of protein synthesis
- released in response to growth hormone releasing hormone (GH_RH) and growth hormone inhibiting hormone (GH_IH)
29
prolactin (PRL)
anterior pituitary
target: mammary glands
- works with other hormones to stimulate mammary gland development and milk production
- released in response to several prolactin releasing hormones (PRH) and inhibited by prolactin inhibiting hormone (PIH)
30
melanocyte stimulating hormone (MSH)
anterior pituitary
target: skin
- from pars intermedia of anterior lobe of pituitary
- stimulates melanocytes of the skin to increase meaning production
- in adults, none are produced
31
oxytocin (OXT)
posterior parathyroid
target: uterus
- increased release in response to childbirth, nursing, sexual arousal, sensory input (both neural and endocrine mechanisms
- stimultes contraction of smooth muscle walls of uterus and mammary gland myoepitheila cells releasing milk
32
what controls secretion rate
negative feedback mechanisms control the secretion rate of the hypothalamus and the pituitary gland
33
feedback loop of hypothalamus and pituitary gland
1) hypothalamus produces a release hormone
2) this triggers release of a hormone by the anterior lobe of the pituitary gland
3) the pituitary hormone stimulates release of a second hormone by the target organ
4) this second hormone surpasses secretion of both the hypothalamic releasing hormone and the pituitary hormone
example:
releasing hormone: TRH --> hormone 1 from pituitary: TSH --> endocrine target organ: thyroid gland --> hormone 2 from endocrine target hormone: Thyroid hormones
releasing hormone: CRH --> hormone 1 from pituitary: ACTH --> endocrine target organ: Adrenal Cortex --> hormone 2 from endocrine target organ: Glucocorticoids
34
thyroid gland
contains c (clear) cells that are in-between follicular cells which secrete calcitonin (aids in calcium regulation)
35
thyroid hormone production and storage steps
1) iodine ions from diet delivered to thyroid gland and taken up by follicular cells
2) enzymes activate iodine and attach to tyrosine portions of thyroglobin molecule
3) t4 and t3 are produced and stored in thyroglobin
4) follicle cells remove thyroglobin from follicle via endocytosis
5) enzymes brekead down thyroglobin releasing thyroid hormones into cytoplasm
6) T3 and T4 diffuse across basement membrane and enter bloodstream
7) 75% of thyroid hormones travel in blood attached to transport proteins (thyroid binding globulins)
- The thyroid gland releases triiodothyronine (T3) and thyroxine (T4). These hormones play an important role in regulation of your weight, energy levels, internal temperature, skin, hair, nail growth
36
effects of thyroid hormones on peripheral tissues
- increase rates of oxygen consumption and energy consumption
- increased heart rate and force of contraction; generally results in a rise of blood pressure
- increased sensitivity to sympathetic stimulation
- maintenacne of normal sensitivity of respiratory centers to changes in oxygen and carbon dioxide concentrations
- stimulation of red blood cell formation and thus enhanced oxygen delivery
- stimulation of activity in other endocrine tissues
- accelerated turnover of minerals in bone
37
what hormone is primary regulator of blood calico ion levels
parathyroid hormone, produced by parathyroid glands
38
parathyroid gland location and structure
- two pairs on posterior surface of thyroid glans
- have two cell populations
1) oxyphil cells (unknown function )
2) parathyroid (chief) cells
- produce parathyroid hormone which increases calcium levels in extracellular fluid
- monitor calcium levels in blood like thyroid c cells
39
specific function of parathyroid hormone
-mobilizies calcium from bone by inhibiting osteoblasts (reduces deposition rate of bone) and increases osteoclasts by releasing growth factors
-enhances reabsorption of CA2+ by kidneys
-stimulates release of calcitrol by kidneys
calcitrol enhances 4th effects and increases ca2+ and PO3-4 aborsppton in intestine
40
function of calcium
muscle contraction, nerves, clotting
41
calcium homeostasis
PTH and calcitonin from thyroid gland have opposing effects
rising calcium in blood
- thyroid gland produces calcitonin --> increased excretion of calcium by kidneys and calcium deposition in bones
- homeostasis is restored as blood calcium levels decline
When blood levels of calcium get too high, the thyroid gland is stimulated to release calcitonin , which inhibits osteoclast activity and stimulates calcium uptake by the bones, but also decreases reabsorption of calcium by the kidneys. All of these actions lower blood levels of calcium. When blood calcium levels return to normal, the thyroid gland stops secreting calcitonin.
decreasing calcium level in blood
- parathyrpid glands secrete parathyroid hormone (PH) --> increased reabsorption of calcium by kidneys, calcium release from bone, increased calictrol production cause ca2+ adsorption from digestive system
- homeostasis is restored as blood calcium levels increase
When calcium is not binding to these receptors, the cells release PTH, which stimulates osteoclast proliferation and resorption of bone by osteoclasts. This demineralization process releases calcium into the blood. PTH promotes reabsorption of calcium from the urine by the kidneys, so that the calcium returns to the blood. Finally, PTH stimulates the synthesis of vitamin D, which in turn, stimulates calcium absorption from any digested food in the small intestine.
42
what are the functions of the adrenal hormones
the adrenal hormones are involved in metabolic regulation, electrolyte balance, and stress response
43
adrenal glands location and structure
-yellowish (from steroid lipids like cholesterol and fatty acids) superior to each kidney
layers
- adrenal capsule (thin outer connective tissue)
- adrenal cortex
* *produces more than 24 steroid hormones called corticosteroids/adrenocortical steroids
* **if corticosteroids are destroyed with adrenal gland, person will die
- adrenal medulla
* *synthesizes epinephrine and norepinephrine
44
adrenal cortex zones and hormones layers
- zona glomerulosa
- zona fasciulata
- zona reticularis
- adrenal medulla
45
zona glomerulosa
adrenal cortex zones and hormones layers
target: kidney
hormones
- mineralocorticoids (primarily aldosterone)
**increases renal absorption of Na+ and water especially in presence of ADH
**accelerates urinary loss of K+
-secretion stimulated by decreased blood pressure and volume through kidney enzyme
46
zona fasciculata
adrenal cortex zones and hormones layers
target: most cells
hormones:
-glucocorticoids are steroid hormones that affect glucose metbaolism
-primary hormones are cortisol and corticosterone
-liver converts some circulating cortisol to cortisone
effects:
- increases rates of liver glucose and glycogen formation
* *stimulates release of amino acids from skeletal muscle and lipids from adipose tissue
* *promote lipid metabolism
* *can have reduce inflammation
- stimulated by acth from anterior lobe of pituitary
47
zona reticularis
adrenal cortex zones and hormones layers
Target: skin, bones, other tissues but minimal effect in normal adults
hormones:
- androgens (male sex hormones) that may be converted to estrogens in the blood stream
```
function
-stimualte pubic hair development before puberty
```
-androgen section is stimulated by ACTH
48
adrenal medulla
adrenal cortex zones and hormones layers
hormone:
- epinephrine and norepinephrine
function:
- increase cardiac activity
- increase blood pressure
- increase glycogen breakdown and blood glucose
-stimualted by sympathetic preganglionic fibers
49
what does the pancreatic islets do
pancreatic islets secrete insulin and glucagon which regulate glucose use by most cells
50
what are the regions of pancreas
1) exocrine pancreas (99% of volume)
- cells (pancreatic acini) form glands and ducts that secrete pancreatic fluid and enzymes with digestive functions
2) endocrine pancreas (1%)
- smalls groups of cells scattered in clusters (pancreatic islets that secrete hormones
51
cells and hormones of endocrine pancreas
alpha cells, beta cells, delta cells, F cells
52
alpha cells
endocrine pancreas hormone and cells
alpha cells
- glucagon: raises blood glucose by increasing liver glycogen
53
beta cells
endocrine pancreas hormone and cells
insulin: lowers blood glucose by increasing glucose uptake and utilization by cells and also increasing glycogen production in liver and skeletal msucles
54
delta cells
endocrine pancreas hormone and cells
produces peptide hormone identical to growth hormone inhibiting hormone
-supresses release of glycogen and insulin
-slows rates of food absorption and enzyme secretion in digestive tract
55
f cells
```
endocrine pancreas hormone and cells
pancreatic polypeptide (PP)
-inhibits gall bladder contraction and reduces digestive activity of pancreas and digestive tract
```
56
glucose homeostaiss
-insulin and glucagon are primary hormones controlling blood glucose levels (have opposing effects)
** as blood glucose rises, beta cells secrete insulin bringing glucose into target cells
**as blood glucose declines, alpha cells secrete glucogen causing liver breakdown of glycogen and and glucagon release
57
what does pineal gland secrete
pineal gland of epithalamus secretes melatonin which affects circadian rhythm
58
diabetes mellitus
characterized by glucose concentrations high enough to overwhelm kidney reabsorption
59
hyperglycemia
abnormally high blood glucose
60
glycosuria
glucose in urine
61
polysuria
excessive urine production
62
clinical problems of diabetes mellitus
- partial or complete blindness
- early heart attacks
- diabetic nephropathy which leads to kidney failure
- abnormal blood flow to neural tissues
- blood flow to distal portions of limbs is reduced
63
type 1 diabtes
- insulin dependent
- inadeqaute insulin production from beta cells
- individuals must receive insulin daily
- often develops in childhood
64
type 2 diabetes
- non insulin dependent
- normal insulin levels but target cells do not repsond properly = insulin resistant
- associated with obesity
- can be treated with diet and exercise
- late type 2 = beta cells are worn out
65
what happens with untreated diabetes
untreated diabetes can cause propels as tissues will repsond in crisis, breaking down proteins and lipids b/c they are unable to absorb glucose from surrondings
66
can cells respond to multiple hormones
because cells have more than one type of receptor, they repsond to multiple hormones at the same time when a cell receives instructions from two hormones simultaneously, there are 4 outcomes
antagonistic
additive
permissive
integrative
67
antagonistic effect
when cells repsond to more than one type of hormone
- obseved effects are weaker than those produced by either hormone acting unopposed
ex: insulin and glucagon
68
additive effect
when cells repsond to more than one type of hormone
- two hormones effect is greater together than the effect each would produce acting alone
ex: the enhancement of glucose sparing action of GH in the presence of glucocorticoids
69
permissive effect
when cells repsond to more than one type of hormone
- first hormone is needed for second hormone to produce effect
ex: epinephrine does not change rate of energy consumption in a tissue unless thyroid hormones are also present
70
integrative effect
when cells repsond to more than one type of hormone
- two hormones may produce different but complimentary effects
- importantnin coordinating diverse physiological systems
ex: the differing effects of calcitrol and parathyroid hormone on tissues involved in calcium metabolism
71
blood pressure homeostaiss
high blood pressure and volume
- stretch receptors in the heart cause the release of natriuretic peptides --> promote loss of Na+ and water at kidneys, surpasses thirst, inhibits released of renin, adh, aldosterone
- overall effect is reduction of blood volume and pressure
low blood pressure
-erythripoties and renin from kidneys are released --> leads to increased fluid intake and fluid retention
72
what is the stress response
the stress response is a predictable response to any significant threat to homeostasis
73
3 phases of stress response (general adaption syndrome)
alarm phase
resistance phase
exhausted phase
74
alarm phase
- immediate sympathetic response to stress
* * epinephrine is dominant hormone
- two main responses
* * energy reserves mobilized (glucose)
* * general fight or flight responses
75
resistance phase
- entered after a few hours of stress
- glucocorticoirds are dominate
- epinephrine, gh, thyroid hormone involved
- overall effect is mobilization of body energy reserves while reserving glucose for neural tissues
76
exhausted phase
- when energy reserves cannot be maintained, resistance phase ends
- organ systems begin to fail
- mineral electrolyte impabalnces contribute to body issues
77
what causes endocrine disorders
overproduction (hyper secretion) or underproduction (hypo secretion) of hormones
78
common causes of hyposecretion
- metabolic factors (key hormone substrate deficiency)
* *hyperthyroidism can be caused from inadequate levels of iodine in the diet
- physical damage (delivery or damage to target cells)
- congenital disorders (unable to produce normal amounts of hormone) due to
* *gland too small
* *required enzymes are abnormal
* *receptros are relatively insesnitive
* *gland cells lack the receptors to become stimulated
79
peptide hormones
-insulin, glucagon, GH, vasopressin (ADH)
80
amines hormones
-thyroxin (T4), tridothyronine (T3), norepinephrine/epinephrne
81
steroids hormones
-testoserone, aldosterone, cortisol, estradiol
82
peptide hormones are synthesized as large precursor hormones called ____ . the hormones are stored in ____ and released from the cell by ___
preprohomrones
secretory vesicles
exocytosis
83
do peptide hormones require a carrier in the blood stream?
no because they are water soluble (hydrophilic)
84
catecholemines (E and NE) are produced in the. ___ of the adrenal glans are are classified as __ hormones since they are derived from ___. stimulation of the chromatin cells causes an influx of __ ions, which causes the vesicles to merge with the plasma membrane and release the hormone by ___.
medulla, amines, tyrosine, Ca, exocytosis
85
are catecholamines water soluble or lipid soluable
water soluable
86
all steroid hormones are derived from ___, which steroid hormone is produced by the ___ present in the cell
cholesterol, enzymes
87
two examples of hormonal regulation of hormones secretion include: 1) the negative feedback of T3 and T4 to decrease __ levels; and 2) the negative feedback or cortisol which decreases both __ and ___ levels
TSH, ACTH, CRH
88
the receptor is activated by the input signal that is the ___. this signal causes a biochemical change in the cell., name the 3 possible changes listed _____
- ____
- ____
hormone
alter plasma membrane permeability
synthesis of proteins
activate of reactive enzymes
89
water soluble proteins such as. ___ and ___ bind to receptors where on the cell?
peptides
catecholamines
plasma membrane
90
lipid soluble hormones such as __ and ___ hormone bind to receptors located ___
steroid
thyrpid
cytoplasm/nucleus
91
the anterior pituitary is composted of __ tisue
epithelial
92
in negative feedback, the target hormone feed back to alter the release of the anterior or hypothalamus hormones thus ___ its own release
decreasing
93
given an example of a hormone that has a negative feedback mainly to the anterior pituitary
T3 and T4
94
give an example go a hormone that has negative feedback to both anterior pituitary and the ventral hypothalamus
prolactin
95
prolactin is unique in that the main ventral hypothalamic hormone regulating its secretion ___ inhibits its release
dopamine
96
___ hormone increases prolactin release
estrogen
97
suckling of an infant cause milk letdown by stimulated what hormone
oxytosin
98
changes in osmolarity detected by chemically sensate neurons in the hypothalamus will alter that hormones level
vasopressin/. adh
99
exicosnaoids are synthesizes from
orgotonic acids
100
whaT are the 2 groups of eicosonoids
prostaglandins and leukotrienes
101
NSAIDs target what
cycloogente enzymes which produced prostaglandins
102
antidiuretic hormone (ADH
posterior pituitary
target: kidney
also known as vasopressin
released in response to variety of stimuli
-primarily increases solute concentration of blood or a decrease in blood pressure and volume
-inhibited by increase in extracellular fluid volume and by alchol
-primary function is to decrease water lost from kidney
-also cause vasoconstriction (narrowing of peripheral blood vessels that helps increase blood pressure)
