Ch. 49 Chemical Signals in Animals Flashcards
0
Q
endocrine system
A
gland & tissues that produce/secrete hormones into the bloodstream
1
Q
hormone
A
any of many different signaling molecules that circulate throughout the plant or animal body
- can trigger characteristic responses in distant target cells @ very low concentrations
- controlled
- big size
- specific function
- result in longer response than the action potential of the CNS
- long lasting effect
- chemical signal
2
Q
animal chemical signals
A
1) present in extremely low concentrations
2) have enormous effects on their target cells
3
Q
properties of electrical impulses
A
1) short-term effect
2) fast response
4
Q
major categories of chemical signals
A
- grouped based on effect produced on cell/organ
1) autocrine signals
2) paracrine signals
3) endocrine signals
4) neural signals
5) neuroendocrine signals
5
Q
autocrine signal
A
a chemical signal that affects the same cell that produced/released it
(ie) cytokines
6
Q
cytokine
A
(autocrine) any of a diverse group of signaling proteins
- secreted largely by cells of the immune system
- stimulates leukocyte production
- recruits cells to site of infection, tissue repair & fever
- FCN: regulate the type, intensity & duration of an immune response
- amplify the response of a cell to a stimulus
7
Q
paracrine signal
A
a chemical signal that diffuse locally& affects neighboring cells
(ie) insulin, glucagon & somatostatin
8
Q
insulin
A
a peptide hormone produced in pancreas in response to HIGH levels of GLUCOSE in blood
- enables cells to absorb glucose
- coordinates synthesis of fats, proteins & glycogen
- paracrine signal
- produced by islets of Langerhan
9
Q
glucagon
A
a peptide hormone produced by the pancreas in response to LOW blood GLUCOSE
- raises blood glucose by triggering breakdown of glycogen & stimulating gluconeogenesis
- paracrine signal
- produced by islets of Langerhan
10
Q
somatostatin
A
a hormone secreted by the pancreas & hypothalamus that inhibits the release of several other hormones
- paracrine signal
- produced by islets of Langerhan
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Q
islets of Langerhans
A
cells in the pancreas that produces insulin, glucagon & somatostatin
12
Q
endocrine signal
A
a chemical signal (hormone) that is released into the bloodstream by a producing cell (gland)
- acts on a distant target cell
- most common
- most effective
13
Q
neural signal
A
neurotransmitters that diffus a short distance from presynaptic cell to a postsynaptic cell, where it binds to a membrane receptor & results in a change in the membrane potential
- very fast
- short-lived
*synapse
14
Q
neuroendocrine signal
A
nerve cells (neurons) that release hormones into the blood or to hormones themselves
- considered hormones
- carried by blood & otro body fluids
- act on distant cells
- do not act on/at synapse
(ie) antidiuretic hormone
(aka) neurohormone
“nerve inside separated”
15
Q
antidiuretic hormone (ADH)
A
a peptide hormone, secreted from the posterior pituitary gland
- stimulates water retention by the kidney
(aka) vasopressin
16
Q
hormone signaling pathways
A
1) endocrine pathway
2) neuroendocrine pathway
3) CNS-to-endocrine pathway
17
Q
endocrine pathway
A
sends hormones directly from endocrine cells to effector cells
signal -> endocrine cell -> effector cell
18
Q
neuroendocrine pathway
A
releases neuroendocrine signals that act directly on effector cells
signal -> sensor cell -> CNS -> effector cell
19
Q
hormones in insects regulate _____.
A
molting & metamorphosis
20
Q
CNS-to-endocrine pathway
A
neuroendocrine signals stimulate cells in the endocrine system, which respond by producing an endocrine signal that acts on effector cells
stimulus -> receptor cell -> endocrine cell -> effector cell
21
Q
steps to shutting down a hormone
A
1) hormones produced by effector cells feed back to endocrine cells, lowering hormone production
2) effector hormone also feeds back to neuroendocrine & neuroendocrine-to-endocrine pathways
3) endocrine signals are released in response to electrical signals, which modulate the signal from the nervous system
22
Q
endocrine gland
A
a gland that secretes hormones directly into the bloodstream or interstitial fluid instead of into ducts
23
Q
hormones in insectes regulate _____.
A
molting & metamorphosis
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major human endocrine glands
1) pituitary gland
2) thyroid gland
3) parathyroid gland
4) kidney
5) adrenal gland
6) pancreas
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pituitary gland
a small gland located directly under the brain
- physically/functionally connected to hypothalamus
- produces/secretes hormones that affect many other glands & organs
- regions: anterior & posterior
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thyroid gland
a gland in the neck that releases thyroid hormone (increases metabolic rate) and calcitonin (lowers blood calcium)
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parathyroid gland
a part of the thyroid gland
| - controls calcium levels (calcitonin)
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polypeptide
a chain of 50+ amino acids linked juntos by peptide bonds
- nonsoluble lipids
- need receptor
- acts @ cell surface
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amino acid derivative
- not lipid soluble
- bind to receptors located in the membranes of target cells
- acts @ cell surface
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steroid
a class of lipid w/ a characteristic 4-ring hydrocarbon structure
- large molecule
- lipid soluble
- acts inside cell
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kidney
one of a paired organ situated @ back of abdominal cavity
- filters blood
- produces urine
- secretes several hormones
- attached to adrenal glands
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adrenal glands
endocrine glands
- sit on top of kidneys
- cortex secretes steroid hormones
- medulla secretes epinephrine & norepinephrine
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major human endocrine glands
1) pituitary gland
2) thyroid gland
3) parathyroid gland
4) kidney
5) adrenal gland
6) pancreas
7) ovary
8) testes
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pancreas
a large gland in vertebrates that has both exocrine & endocrine functions
- secretes digestive enzymes into a duct connected to the intestine
- secretes several hormones (insulin & glucagon) into the bloodstream
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a single hormone can
exert a variety of effects
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ovary
egg-producing organ of a female animal
seed-producing structure in female part of a flower
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testis
sperm-producing organ of a male animal
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exocrine gland
a gland that secretes some substance through a duct into a space other than the circulatory system
- major role in puberty acne
(ie) digestive tract or skin surface
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chemical families
1) polypeptides
2) amino acid derivatives
3) steroids
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secretin
a peptide hormone produced by cells in the small intesting in response to the arrival of food from the stomach
- stimulates secretion of bicarbonate (HCO3) from the pancreas
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epinephrine
a catecholamine hormone produced & secreted by adrenal medulla
- triggers rapid responses related to fight-or-flight response
(aka) adrenaline
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thyroxin (T4)
a lipid-soluble hormone derived from the amino acid tyrosine
- produced/secreted by thyroid gland
- regulates cellular metabolism
- (humans) converted to active triiodothyronine (T3) in the liver
- lipid soluble
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thyroxin (T4)
a lipid-soluble hormone derived from the amino acid tyrosine
- produced/secreted by thyroid gland
- regulates cellular metabolism
- (humans) converted to active triiodothyronine (T3) in the liver
- lipid soluble
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to affect a target cell, all polypeptides & most amino acids derivatives
bind to receptor on the cell surface
45
lipid-soluble hormone (steroids) can diffuse
through the plasma membraane & bind to receptors inside the cell
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growth hormone (GH)
a peptide hormone produced/secreted by anterior pituitary
- promotes lengtheing of long bones in children and muscle growth, tissue repair & lactation in adults
- stimulates mitosis & growth
- determines how fast to grow
(aka) somatotropin
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what happens when the pituitary gland of an animal is removed?
animal stops growing
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single hormone can
exert a variety of effects
49
several hormones may
affect the same aspect of physiology
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hormones coordinate the activities of cells in 3 areas
1) development growth & reproduction
2) response to environmental challenges
3) maintenance of homeostasis
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growth + sex hormones
- promotes cells division
- promotes growth
- promotes sexual differentiation
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metamorphosis
transition from 1 developmental stage to another
- requires a lot of energy
- (during) immune system shuts down, makes more susceptible to diseases/viruses
(ie) larval to adult form of an animal
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triiodothyronine (T3)
thyroid hormone responsible for most changes observed in metamorphosis
- produced in response to signals from brain
- lipid soluble
- derived from amino acid tyrosine
- increases cellular metabolism
- has stronger effect than thyroxine (T4)
54
ways juvenile amphibians resond to increased levels of T3
1) grow & form new structures: legs
2) cells die: tadpole tail
3) cell change structure & function
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larva
an immature stage of an animal species in which the immature & adult stages have different body forms
- juvenile stage
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pupal case
a tough case that juveniles secrete during metamorphosis
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metamorphosis depends on interactions between
juvenile hormone (JH) & ecdysone
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juvenile hormone (JH)
an insect hormone that prevents larvae from metamorphosing into adults
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ecdysone
an insect hormone that triggers either molting (to a larger larval form) or metamorphosis (to the adult form)
- depends on the level of juvenile hormone (JH)
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if juvenile hormone (JH) levels are high, ecdysone triggers _______.
growth of juvenile by molting
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if juvenile hormeon (JH) levels are low, ecdysone triggers ________.
metamorphosis and the transition to adulthood & sexual maturity
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types of metamorphosis
1) complete
| 2) incomplete
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incomplete metamorphosis
a type of metamorphosis in which the animal increases in size from one stage to the next, but does not dramatically change its body form
(aka) hemimetabolous metamorphosis
(ie) humans & animals
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complete metamorphosis
a type of metamorphosis in which the animal completely changes its form
- includes a distinct larval stage
(aka) holometabolous metamorphosis
(ie) butterfly
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primary sex determination
events early in development that dictate whether the sex organs (gonads) of the vertebrate embryo become male or female
- depends on genes on sex chromosomes
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hormone produced by testes
1) testosterone
| 2) Mullerian inhibitory substance
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testosterone
a steroid hormone
- produced/secreted by testes
- stimulates sperm production, various male traits & reproductive behaviors
68
Mullerian inhibitory substance
a peptide hormone
- secreted by embryonic testis
- causes regression (withering away) of the female reproductive ducts
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estradiol
major estrogen
- produced by ovaries
- stimulates development of female reproductive tract, growth of ovarian follicles & growth of breast tissue in mammals
70
sex hormones play a role in
the juvenile to adult transition
(ie) puberty
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sex hormone play a key role in:
1) development of the reproductive tract in embryos
2) reproductive tract maturation during transition from childhood to adulthood
3) regulation of spermatogenesis & oogenesis in adults
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puberty
the various physical & emotional changes that an immature human undergoes in reaching reproductive maturity
- period when such changes occur
73
photoperiod
the amount of time per day (usually in hours) that an organism is exposed to light
- stimulates release of sex hormones in some mammals, birds & lizards
74
how photoperiod affects sex hormone release
1) photoreceptors send signals to the hypothalamus
2) hypothalamus initiates a series of signals that stimulate sex hormone production
3) in some animals, the photoreceptors are located in the retina, which signals the pineal gland
4) pineal gland secretes melatonin, which sends signals to the hypothalamus
75
pineal gland
an endocrine gland located in the brain
- detects light
- secretes/activates melatonin based on amount of light
76
melatonin
a hormone produced by the pineal gland
- regulates sleep/wake cycles
- regulates seasonal reproduction in vertebrates
- maximum secretion occurs at night
- concentration decreases during daylight hours
77
a decline in melatonin stimulates hypothalamus, which causes
sex organs to produce sex hormones
78
endocrine disruptor
an exogenous chemical that interferes w/ normal hormonal signaling
- many are xenoestrogens
79
xenoestrogen
foreign chemicals that bind to estrogen receptors or otherwise induce estrogen-like effects
80
examples of endocrine disruptor
1) atrazine, an herbicide - causes reproductive abnormalities
2) bisphenol (BPA) - causes abnormal development of the brain & reproductive tissue
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fight-or-flight response
rapid physiological changes that prepare the body for emergencies
- increased heart rate
- increased blood pressure
- decreased digestion
- triggered by sympathetic nervous system
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epinephrine
a catecholamine hormone produced/secreted by adrenal medulla
- triggers rapid responses related to the fight-or-flight response
- short-term stress
(aka) adrenaline
83
cortisol
a steroid hormone produced/secreted by the adrenal cortex
- increases blood glucose
- prepares body for stress
- major glucocorticoid hormone
- ensures continued availibility of glucose for the brain
- may cause cardiovasuclar disease
- long-term stress
(aka) hydrocortisone
84
glucocorticoid
a class of steroid hormones
- produced/secreted by adrenal cortex
- increases blood glucose
- prepares body for stress
(ie) cortisol & cotricosterone
85
how cortisol controls blood sugar in humans
1) induces liver to produce enzymes that generate glucose from amino acids
2) changes adipose tissue & resting muscles resistant to insulin so they will not take in glucose
3) promotes the release of fatty acids for use by the heart & muscles
86
how are hormones involved in homeostasis?
1) sensory receptors monitor conditions relative to a set point
2) an integrator processes info from the sensor
3) effector cells return the condition to the set point
87
parabiosis
an experimental technique for determining whether a certain physiological phenomenon is regulated by a hormone
- consists of surgically uniting 2 individuals so that hormones can pass between them
- may also be natural (conjoined twins)
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leptin
a hormone produced/secreted by fat cells (adipocytes)
- stabilizes fat-tissue mass by inhibiting appetite & increasing energy expenditure
- reduces appetite in response to increase in adipose tissue mass
89
If ADH is present, there will be a _______ (large/small) volume of urine.
small
90
If ADH is not present, there will be a _______ (large/small) volume of urine.
large
91
antidiuretic hormone (ADH)
a peptide hormone
- secreted from posterior pituitary gland
- stimulates water retention by the kidney
- increases permeability of the kidney's collecting ducts to water (water reabsorbed from urine)
(aka) vasopressin
92
aldosterone
a hormone that stimulates the kidney to conserve salt & water (electrolyte)
- promotes sodium retention
- produced in adrenal cortex
93
mineralocorticoid
a class of steroid hormones
- produced/secreted by adrenal cortex
- regulate electrolyte levels & overall volume of body fluids
- related to aldosterone & adrenal hormones
94
erthyopoietin (EPO)
a peptide hormone
- released by kidney in response to low blood-oxygen levels
- stimulates bone marrow to produce more RBC
95
The more red blood cells, the _______ (higher/lower) the oxygen-carrying capacity of the blood.
higher
96
hormones are regulated by
CNS, brain & spinal cord
97
adrenocorticotropic hormone (ACTH)
a peptide hormone
- produced/secretedby anterior pituitary
- stimulates release of steroid hormones (cortisol/aldosterone) from adrenal cortex
98
corticotropin-releasing hormone (CRH)
a peptide hormone
- produced/secreted by the hypothalamus
- stimulates the anterior pituitary to release ACTH
99
what happens when feedback mechanism fails (CRH, ACTH, cortisol)?
there will be high levels of ACTH in the blood
100
epinephrine
a catecholamine hormone produced/secreted by adrenal medulla
- triggers rapid responses related to the fight-or-flight response
- released for short-term stress
(aka) adrenaline
101
cortisol
a steroid hormone produced/secreted by the adrenal cortex
- increases blood glucose
- prepares body for stress
- major glucocorticoid hormone
- ensures continued availibility of glucose for the brain
- may cause cardiovasuclar disease
- other tissues/organs become expendable (abandoned/destroyed)
- released for long-term stress
- inhibits CRH & ACTH
(aka) hydrocortisone
102
Cushing's disease
a human endocrine disorder
- inability of cortisol to suppress hormone production
- caused by loss of feedback inhibition of cortisol on ACTH secretion
- high ACTH levels
- high cortisol levels
- wasting of body protein reserves
103
hypothalamic-pituitary axis
the functional interaction of the hypothalamus & anterior pituitary gland, which are anatomically distinct but work juntos to regulate most of the other endocrine glands in the body
104
neurosecretory cell
a neuron that produces/secretes hormones into the bloodstream
- primarily found in the hypothalamus
(aka) neuroendocrine cell
105
relationship btwn ADH & oxytocin
1) both produced by neurosecretory cells of the hypothalamus
2) stored in the posterior pituitary
3) released into the bloodstream
106
hormones that the anterior pituitary gland produces
1) ACTH
2) follicle-stimulating hormone (FSH)
3) lutenizing hormone (LH)
4) growth hormone (GH)
5) prolactin
6) thyroid-stimulating hormone (TSH)
107
follicle-stimulating hormone (FSH)
a peptide hormone
- produced/secrete by the anterior pituitary
- (females) stimulates growth of eggs & follicles
- (males) stimulates sperm production
108
lutenizing hormone (LH)
a peptide hormone
- produced/secreted by the anterior pituitary
- (females) stimulates estrogen production, ovulation & formation of the corpus lateum
- (males) stimulates testosterone production
109
prolactin
a peptide hormone
- produced/secreted by the anterioro pituitary gland
- (female) promotes milk production
- has a variety of effects on parental behavior
- has effect on seasonal reproduction in other vertebrates
110
thyroid-stimulating hormone (TSH)
a peptide hormone
- produced/secreted by the anterior pituitary
- stimulates release of thyroid hormones from thyroid gland
111
modes of controlling epinephrine
1) neurotransmitters change gene expression in neurons
| 2) hormones change gene expression in target cells
112
Differences in _________ of hormones influence where a target cells receives the chemical message
lipid solubility
113
estradiol
major estrogen
- produced by ovaries
- stimulates development of female reproductive tract
- (mammals) stimulates growth of ovarian follicles & growth of breast tissue
- most important estrogen
- receptor found only in the nucleus of the targeted tissue
114
estrogen
a class of steroid hormones
- includes: estradiol, estrone & estriol
- promote female-like traits
- secreted by gonads, fat tissue & otro organs
- lipid soluble
- enters cell through plasma membrane
115
characteristics of steroid hormones
1) lipid soluble
2) enter a target cell
3) bind to receptors inside the cell
4) causes a change in gene expression
116
zinc finger
a distinctive DNA-binding region for steroid-hormone receptors
117
how change in gene expression occurs
1) interfere w/ transcription
| 2) bind directly to DNA, the steroid hormone receptor complex binds to the hormone-response gene
118
phosphorylase
an enzyme that catalyzes the formation of glucose from glycogen by triggering a signal transduction cascade
- activated by epinephrine
119
cyclic adenosine monophosphate (cAMP)
a small molecule
- derived from ATP
- widely used by cells in signal transduction & transcriptional control
- second messenger
120
second messenger
a nonprotein signaling molecule produced/activated inside a cell in response to stimulation @ the cell surface
- commonly used to relay the message of a hormone or other extracellular signaling molecule
121
cAMP-dependent protein kinase A
(triggers signal transduction cascade)
enzyme that responds to cAMP
- phosphorylated phosphorylase kinase, which phosphorylates phosphorylase
122
steps leading up to signal transduction cascade
1) epinephrine binds to a surface receptor
2) the enzyme adenylyl cyclase (AC enzyme) is activated
3) the AC enzyme catalyzed ATP to cAMP
4) cAMP initiates the signal transduction cascade
123
signal transduction cascade
a series of enzyme-catalyzed phosphorylation reactions
- commonly used in signal transduction pathways to amplify
- convey a signal inward from plasma membrane
- diverse
- complex
124
steps leading up to signal transduction cascade
1) epinephrine binds to a surface receptor
2) the enzyme adenylyl cyclase (AC enzyme) is activated
3) the AC enzyme catalyzed ATP to cAMP
4) cAMP initiates the signal transduction cascade
125
model for phosphorylation cascade
1) cAMP transmits signal from the cell surface to the signaling cascade
2) cAMP + subsequent phosphorylation events amplify the original signal from epinephrine
