Test 1 Flashcards
(99 cards)
1
Q
what was berthold’s conclusion
A
- There must be a ‘secretory, blood-borne factor” responsible for the effects of the male chicken developing
2
Q
Horsley and Murray conclusion
A
- Successfully used organotherapy
- Horsley removed thyroids in monkeys and they developed hypothyroidism
- Murray developed extract from sheep thyroid which was a successful replacement treatment
3
Q
Bayliss and Starling
A
- First to put a name to hormones
- Pancreas’s only connection with body is via blood vessels which means there must be a chemical in the blood.
3
Q
Halban conclusion
A
- Glands don’t communicate through nerves but instead internal secretions
4
Q
How to design endocrine experiments
A
REMOVE IT AND PUT IT BACK (RORO)
- Remove
- Observe
- Replace
- Observe restoration
5
Q
Hormone
A
Regulatory substance produced in an organism and transported in tissue fluids, such as blood, to stimulate specific cells or tissues into action
6
Q
What are the two types of local communication
A
autocrine
paracrine
7
Q
How does autocrine work?
A
substance released by the cell as a self regulator
8
Q
How does paracrine work?
A
substance is released to a target cell nearby. This results in quick responses that only last a short time
9
Q
Long Distance messenger
A
Endocrine
substances are released and travel to distant cells through the blood. relatively slow
10
Q
3 types of hormones
A
peptides
steroids
monoamine hormones
11
Q
What determines transport
A
water solubility
12
Q
hydrophobic
A
not water soluble. hormone needs help moving through the blood
13
Q
hydrophilic
A
water soluble. can move freely through the blood
14
Q
what influences hormone-cell interactions
A
lipid solubility
15
Q
lipophilic
lipophobic
A
lipophilic can move easily across membrane barriers while lipophobic needs help moving across
16
Q
Characteristics of peptide/protein hormones
A
structure: chain of amino acids
water soluble
lipid insoluble
17
Q
how many amino acids on each
peptides
polypeptides
proteins
glycoproteins
A
peptides- less than 20
polypeptides- 20 -100
proteins- more than 100
glycoproteins - carbohydrate added
18
Q
Peptide synthesis
A
encoded by genes (translation and transcription)
original translate protein is called pre-prohormone or prohormone these must undergo translational modifications
19
Q
peptide storage
A
stored in endocrine gland in secretory vesicles until release is triggered
20
Q
peptide signaling
A
binds to cell surface receptors - fast 2nd messenger signals
21
Q
Characteristics of Steroid Hormones
A
chemical strucuture - carbon ring
hydrophobic
lipidphilic
all derived from cholesteral
22
Q
where are steroid hormones produced
A
adrenal glands, gonads, and some additional tissue
23
Q
steroid storage
A
cannot be stored. made on demand
24
steroid signaling
binds to intracellular receptors; slow genomic effect
25
Specificity
receptors bind to only one hormone or class of hormone
26
characteristics of hormones
distinguish a hormone from other molecules with similar structures
bind to hormone even when concentration is low
conformational change when bound to the hormone
catalyze biochem events
27
Types of Receptors
Intracellular (in cytosol and nucleus; steroids and thryoid hormones)
membrane-bound (on cell surface; peptide and most monoamines)
28
what influences sensitivity of target cells
1. hormone concentration
2. receptor affinity
3. # of receptors
29
negative feedback regulation
hormones or their physiological responses inhibit further secretion. Most hormones are regulated this way.
30
positive feedback
hormones cause even more hormones to be
released. Drive for secretion becomes progressively more
intense until it terminates with some cataclysmic event
31
down-regulation
tissue decreases receptors
less sensitive to hormone
32
up-regulation
tissue increases receptors
more sensitive to a hormone
seen when hormone levels are chronically low
33
synergistic effects
2 hormones with similar effects produced an amplified response
34
antagonistic effect
2 hormones have opposing effects, usually act to maintain homeostasis
35
permissive effects
one hormone enables another to act, even though the hormone itself does not initiate the response. 2 hormones acting together may produce an effect neither can make alone
36
agonists
bind to the receptor and
produce a similar response to the intended hormone because they are so structurally similar
37
antagonistic
bind to the receptor
but don’t produce a response, because they are just structurally similar enough to have a high
affinity but not to activate it. Prevents the hormone from binding.
38
heat shock proteins
bind to the intracellular receptor when hormone is not present
released when hormone arrives
39
Hormone response element
portion of dna receptors bind to.
40
2 main forms of membrane-bound receptors
2nd messenger (G-protein)
intrinsic enzymatic activity (tyrosine kinase)
41
G-protein signaling basics
3 subunits
42
effector enzyme
target of activated G
proteins that produce second messengers
43
second messengers
intracellular signaling
molecules released by the cell in response to
exposure to a hormone
44
alpha subunit
Alpha (s) - adenylyl cyclase - cAMp
Alpha (I) - adenylyl cyclase - cAMP
Alpha (q) - phospholipase C - IP3/calcium
45
Serotonin as neurotransmitter
mood
feelings of relaxation and sleep
memory processing
cognition/learning
46
serotonin as hormone (in gut)
satiety
digestion/nutrients absorption
gut motility
47
Dopamine as neurotransmitter
motivation/pleasure seeking
cognition/memory
fine tuning of motor functions
48
dopamine as hormone
secreted by hypothalamus to regulate
prolactin secretion (“prolactin-inhibiting
hormone”)
49
dopamine mesolimbic pathway
Dopaminergic neurons project from ventral tegmental area (VTA) to nucleus accumbens (NA)
* NA is part of the limbic system - network of connected structures that influence emotions, motivation, and memory
* Functions: motivation, emotions, reward, and addiction
50
dopamine mesocortical pathway
* Dopaminergic neurons project from
ventral tegmental area (VTA) to the
cortex (mostly frontal lobe)
* Functions: cognition and emotions
51
Dopamine nigrostriatal pathway
* Dopaminergic neurons project from
substantia nigra to striatum and
basal ganglia
* Functions: voluntary movement
52
Dopamine tuberinfundibular pathway
* Dopaminergic neurons project from
hypothalamus to pituitary
* Dopamine is released into circulation
functions: inhibits prolactin release
53
Dopamine and Parkinson's
Parkinson’s Disease: lose ability to control movements due to the death of dopamine secreting cells
54
Dopamine and Schizophrenia
Dopamine hypothesis of schizophrenia:
* Too much dopamine in the mesolimbic
pathway - hallucinations
* Too little dopamine in the mesocortical pathway - cognitive symptoms
55
grows out of the digestive tract of the embryo
anterior pituitary
56
anterior pituitary cell types
acidophils
basophils
chromophobes
56
extension of the brain
posterior pituitary
57
posterior pituitary cell types
nerve cells
58
connects to the hypothalamus via the hypophyseal portal system (blood vessels)
Anterior Pituitary Lobe
59
connects to the hypothalamus via neurons
posterior pituitary lobe
60
posterior pituitary has 2 regions
* Pars nervosa – largest region and where most hormones are stored
* Infundibular stalk – connects the pars nervosa to the base of the brain
61
largest region and where most hormones are stored
pars nervosa
62
connects the pars nervosa to the base of the brain
infundibular stalk
63
Posterior Pituitary function
does not produce hormones. Just stores and secretes two protein hormones.
Arginine vasopressin
Oxytocin
Hormone secretion is regulated by the hypothalamus via nerve cells
64
Arginine Vasopressin
Target organs are kidneys and blood vessels
65
2 major vasopressin receptors
V1- located on blood vessels and stimulates vascular smooth muscle contraction
V2- located on kidneys and stimulates reabsorption of water into the blood
66
Regulated by baroreceptors in blood vessels that detect decreases in blood
pressure/volume and signal the hypothalamus to trigger secretion of vasopressin
V1 - Vasopressin
67
Regulated by osmoreceptors that
detect increases in osmolality and
signal secretion of ADH
V2 - Anti-Diuretic Hormone
68
Oxytocin Functions
The primary target organs are muscles in the:
Uterus - stimulates the uterine muscles
to contract during childbirth
Breasts - promotes ejection of milk
through ducts during lactation
69
what is the love hormone
oxytocin
70
Anterior Pituitary Anatomy
Pars Distalis
pars intermedia
pars tuberalis
71
largest region and where most hormones are produced
pars distalis
72
resides next
to the posterior pituitary;
produces one main hormone
pars intermedia
73
extends from pars distalis and wraps around the infundibulum, contains
blood vessels
pars tuberalis
74
produces
and secretes most of the
hormones of the pituitary
anterior pituitary
75
Hormone secretion is
regulated by the
hypothalamus via the
hypophyseal portal
system
76
pituitary cell type that contains polypeptides
acidophils
77
pituitary cell type that contains glycoproteins
basophils
78
pituitary cell type that contains minimal hormone content
chromophobes
79
secreted from acidophils
prolactin and growth hormone
80
secreted from basophils
FSH
LH
Thyroid stimulating hormone (TSH)
ACTH
81
corticotropin hormone - CRH - Pituitary (acth)- adrenal hormone
HPA axis
82
GnRH - LH and FSH - gonadal hormone
HPG axis
83
thyrotropin releasing hormone - TRH - TSH - thyroid hormone
HPT axis
84
Its only known physiological role is to
stimulate secretion of thyroid
hormones
(T3 and T4) regulate metabolic
rate and energy expenditure
TSH
85
Targets the gonads and promotes secretion of sex steroids
FSH and LH
86
promotes growth of ovarian follicles and stimulates sperm
production in testes
FSH
87
induces ovulation and stimulates secretion of sex steroids from
ovaries and testes
LH
88
Regulation of FSH and LH Secretion
LH is favored with fast pulses
FSH is favored with slow pulses
89
Targets the adrenal glands and promotes glucocorticoid secretion
(cortisol and/or corticosterone)
ACTH
90
plays a role
in metabolism, immune
function, and stress responses
Hypothalamic-Pituitary-Adrenal Axis
91
is stimulated by the
hypothalamic secretion of prolactin-
releasing hormone
Main function: promote lactation for breastfeeding
Prolactin
92
targets most cells in the body, but primarily bone, muscle, and liver where it promotes protein synthesis and tissue building.
Growth Hormone
93
Growth hormone is inhibited by hypothalamic secretion of
somatostatin
94
is characterized by excess growth hormone after puberty, often because
of a non-cancerous tumor on the pituitary gland.
Acromegaly
95
is characterized by excessive growth in children when growth hormone levels are too high before puberty. Typically caused by a non-cancerous pituitary
tumor.
gigantism
96
is characterized by short stature with normal
body proportions and normal mental development. Adult height is less than 4’10”. Can be present at birth or develop later.
Pituitary dwarfism
97
