BIOL 544 EXAM 3
Which of these processes is part of crossbridge cycling in sarcomeres?
A)ATP binds to myosin, causing myosin head to detach from actin B) myosin head performs power stroke, pulling on thin filament C) myosin head is reset or bent back like a spring D) myosin head with its bound ADP attaches to actin
Which of these pituitary hormones is not released in response to a releasing hormone from the hypothalamus?
ADH
posterior pituitary
ADH and oxytocin hormones from hypothalamus NOT synthesized from pituitary
The major physiological difference between single-unit smooth muscle and multi-unit smooth muscle
Action potentials can spread from cell to cell in single-unit, but not in a multi-unit muscle
fast twitch oxidative
Aerobic, respond rapidly to neural stimulation, break down of ATP more rapidly, less blood supply, fewer and smaller mitochondria than slow-twitch
fast glycolytic
Anaerobic, fast, less mitochondria and myoglobin
Sinuous motion
, lateral muscular waves
Excitation-contraction coupling:
- Calcium binds to calmodulin. - Causes phosphorylation of myosin light chain kinase (MLCK). - No tropomyosin
Ecdysis Triggering Hormone (ETH)
- Cooordinates contractions that allow final escape from the old cuticle.
water soluble chemical messengers
-bind to PM receptors -cannot diffuse through cell -causes intracellular signaling -fast response -ion channels, g-proteins, receptors with kinase activity
Lipid soluble chemical messengers
-bind to intracellular receptor -diffuse through PM -influence gene transcription -slower response, but sustained -steroids
smooth muscle
-control fluid movement, sphincters -little fatigue -low O2 use
With the tripod, gait insect moves
. the left front leg and the right middle leg and the left hind leg together
termination of hormone activation
1. alter receptor 2. phosphorylate receptor 3. endocytosis and degradation of receptor 4. degradation after binding to nuclear chromatin
locust jump sequence
1. cocking behavior 2. co-cotraction phase 3. trigger phase
corpus allatum
JH
calcitonin
Lowers blood calcium levels
prostaglandins
Modified fatty acids that are produced by a wide range of cells. -local chemical mediators
proctolin
Muscular contraction
brain
PTTH
Pheromone-biosynthesis-activating neuropeptides (PBAN)
Regulate sex pheromone biosynthesis
catecholamines prolong
SNS response
thyroid hormones
T3 and T4 -lipid soluble
What will happen to the muscle contraction if ATP is unavailable?
The muscle becomes rigid due to failure of cross-bridges to detach from actin filaments.
anterior pituitary
Tropic: stimulates other glands to release their hormones -releasing and inhibiting hormones
What is needed to release calcium from the sarcoplasmic reticulum
a muscle membrane depolarization. b. interaction of DH receptors with R receptors.
Steroids are hormones which
a) diffuse randomly into and out of nontarget cells without binding to receptors. b) promote metabolic changes which are long-lasting. c) are retained preferentially by receptor protein molecules in target cells.
A deficiency in dietary iodine can cause
a) hypothyroidism (cretinism). b) a slowing of mental functions. c) a low metabolic rate. d) a goiter.
When a certain gland extract gland is applied to a variety of cells, only a few cells respond. When a G-Protein inhibitor is first applied to these cells and then the extract is applied, these few cells still respond. Therefore, the gland extract may contain
a) lipid soluble hormone b) a steroid c) insulin
slow twitch oxidative
aerobic, contract slowly, smaller in diameter, better blood supply, more mitochondria, more fatigue-resistant than fast-twitch.
jumping
aided by cuticular flexion
flying
aided by cuticular flexion at wing and whole thorax
swimming
aided by hairs, special appendages
inhibitory g protein
alpha receptor
Organisms in which the circulating body fluid is NOT distinct from the fluid that directly surrounds the body's cells are likely to have
an open circulatory system
Undulatory movement
anterior + posterior waves, typical of moth & butterfly caterpillars.
indirect flight muscles
are attached to the thorax, changing the shape of the thorax and moving the wings up or down. -asynchronnous
direct flight muscles
are directly connected to the bases of the wings and move the wings up or down
Direct flight muscles
attached to wing itself -synchronous muscles elevators contract--> depressors contract
The second messenger model explains the mode of action of
b)peptide hormones c) prostaglandins
stimulatory G protein
Beta receptor
phospholipase C
breaks down PIP2 into IP3 and DAG
twitch
brief increase in tension due to cross-bridge activity
IP3
causes Ca2+ to be released from the ER and complexes with calmodulin
Ca bound to calmodulin
causes enzyme to be active
Hormones are signals used in the chemical communication between
cells within the same organism
chronotropic control
changes in endogenous neuronal rhythmicity
Which phase occurs first in sequence during the locust jump?
cocking behavior
dense bodies in smooth muscle
connected to actin
oxytocin
contraction of smooth muscle of uterus during labor
histidine
converted to histamine (NT)
Amine hormones
derivatives of tyrosine -catecholamines -thyroid hormones
The same hormone can result in different end effects in the same cell or tissue due to
divergent action
Catecholamines
dopamine, norepinephrine, epinephrine -water soluble
prothoractic gland
ecdysone
cytokines
enhance immune responses
The energy used for muscle contractions after 30 minutes mostly comes from
fatty acids
alpha cells
glucagon
Which hormones promote gluconeogenesis?
glucocorticoids and growth hormone
Glucocorticoids stimulate
gluconeogenesis
Epinephrine activates the cyclic AMP pathway in liver cells. In this example, epinephrine is a ____________ and c-AMP is a _____________.
hormone, second messenger
The specific action of hormones is due to
hormone-specific receptors in target cells
DAG signaling
important in cell growth and differentiation
A motor unit in muscles
includes all muscle fibers connected to one motor axon.
Cortisone and cortisol are hormones released from the adrenal gland. Their function is
increase blood-glucose levels.
PTH (parathyroid hormone)
increases blood calcium
Thyroid hormones
increases metabolism
Which type of insect muscle allows for the highest wing beat?
indirect muscles
Which hormone(s) would most likely be released in increased amounts in response to HIGH blood-glucose levels (hyperglycemia)?
insulin
Type 2 diabetes
is caused by a reduction sensitivity in target cells
Type 1 diabetes
is due to loss of beta cells in the pancreas.
ED and a high concentration of JH
larval to larval molt
ED and a low JH
larval to pupal molt.
walking
leg strokes
type 1 diabetes
loss of beta cells
The primary purpose of the endocrine system is
maintenance of homeostasis
Fly halteres
modified hindwing -oscillate opposite to wing beat
Glucocorticoids produce
more glucose.
The thick filament of a myofibril of a skeletal muscle contains a protein called
myosin
growth hormone
nontropic and tropic effects
prolactin and MSH
nontropic effects
chrysalis
outer cuticle is skin of last larvel instar
Whip-like
posterior + anterior waves
Which of these is a neurosecretory organ rather than a true endocrine gland?
posterior pituitary
tryptophan
precursor for serotonin and melationin
Glucagon
primarily affects liver cells -increases ketogenesis
major types of insect metamorphasis
prometaboly, neometaboly
NO
promotes vasodialation
The T-tubules
provide a means of rapidly transmitting the AP from the surface into the central portions of the muscle fiber
ED and no JH
pupal to adult molt.
hypothalamus
recieves and integrates nerve signals from CNS
type 2 diabetes
reduced sensitivity of insulin target cells
The primary role of calcium in the activation of skeletal muscle is to
remove the inhibition of the reaction between actin filaments and myosin filaments.
episodic control
respomse-stimulus coupling: responsive to physiological demands
Hyperthyroidism
results in an increased heart rate.
beta cells
secrete insulin
delta cells
secrete somatostatin (GH inhibiting hormone)
cAMP cascade
signal, reception/transduction, amplification, second messenger, internal regulator, tissue specific/ kinase specific effectors, cell responses
prostaglandins enhance
smooth muscle contranction
Eclosion hormone (EH)
stimulates Inka cells to secrete PETH and ETH -ONLY IN ADULT ECDYSIS
growth factor
stimulates proliferation and differentiation
Insects have the following muscle type(s):
striated muscles
biochemical amplifacation
substrate+enzyme--> product+ enzyme -if product is another enzyme, reaction has a snowball effect
•Bursicon
tanning/hardening of new cuticle after molting during larval development
receptor specificity
the ability of a receptor to bind only one type or a limited number of structurally related types of chemical messengers
The difference between a muscle twitch and tetanus is due to
the duration of the active state of the muscle.
What is the role of calcium in muscle contractions
to bind with troponin, changing its shape so the actin filament is exposed
click point
unstable intermediate in indirect flight muscles
GLUT 2 transporter
used in liver cells to get glucose in
GLUT 4 transporter
used in most cells to get glucose in
Diuretic hormone (DH)
water balance
ADH
water reabsorption vasoconstriction increase blood pressure
tetanus
when stim. of muscle continues and tension increases maximally
enzymes involved in PG synthesis
COX 1 & 2
The following group of chemicals is NOT a major class of hormones
Carbohydrates
Pre-ecdysis Triggering Hormone (PETH)
Coordinates muscle contractions that pull epidermis away from old cuticle.
The primary role of calcium in the activation of smooth muscle is to
activate myosin molecules so they can interact with actin filaments
second messengers
Cyclic nucleotides DAG IP3 Ca2+ -phosphorylate a protein
Secretion of glucocorticoids is promoted by
a. stress b. a diurnal rhythm c. corticotropin releasing hormone d. adrenocorticotrophic hormone
When a certain gland extract gland is applied to some cells, these cells respond by starting cell division. However, when a c-AMP inhibitor is first applied to the cell and then the gland extract is applied, the cells do not divide. Therefore, the gland extract most likely contains
a.c-AMP b. a peptide hormone
titin
act as spring mechanisms to keep myosin centered