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