chapter1 homeostasis and cellular signaling

chemical messengers that travel via blood stream to an target cell is called what

hormones

what is the function of IP3

increase Ca++ concentration by opening Ca++ ion channels

IGF

insulin-like growth factors

once an hormone has bind to its receptor, how does this binding affect the transducer?

it will cause an conformational change where GDP is released and replaced with GTP

what is the function of AC

it will take ATP and convert it to cAMP

adding an phosphate to an protein is an ____________

kinase

Ca++ concentration are ____________ in cytosol and _____________ outside the cell and ___________

low; ER

MAP kinase pathway can cause proliferation in what division

mitosis

PDFG

platelet derived growth factor

afferent neurons conduct signals from ___________ to __________

receptors; CNS

transducer activates______________ which interacts with a target cell

second messenger

cAMP and cGMP are classified as A) first messenger B) receptor C) transducer D) effector E) second messenger

secondary messenger

they bring the stimuli from the sensors (e.g., skin, eyes, ears) to the CNS is called what type of neuron?

sensory or afferent

Nitric oxide mediates this effect on vascular smooth muscle: A) smooth muscle relaxation B) smooth muscle contraction C) no effect

smooth muscle relaxation

Which of the following is an example of a positive feedback loop? A) A neuron is stimulated, thus opening membrane channels to allow sodium ions to leak from the extracellular fluid to the intracellular fluid. This causes more membrane channels to open, thus allowing more sodium ions to enter the intracellular fluid. B) Baroreceptors notify the brain that the blood pressure has increased. The brain then notifies the blood vessels to dilate, thus lowering the blood pressure. C) Low levels of glucose in the blood cause the pancreas to release less insulin (a hormone that lowers blood glucose). D) Elevated body temperature is sensed by cells in the brain. As a result, sweat is produced, and heat is lost as the water in the sweat evaporates. E) An auto factory produces 1000 cars per week. The sales office could sell 1200 cars per week. Extra production personnel are added at the factory to meet the sales demand.

A neuron is stimulated, thus opening membrane channels to allow sodium ions to leak from the extracellular fluid to the intracellular fluid. This causes more membrane channels to open, thus allowing more sodium ions to enter the intracellular fluid.

Homeostasis is the condition in which the body maintains: A) The lowest possible energy usage B) A relatively stable internal environment, within limits C) A static state with no deviation from preset points D) A changing state, within an unlimited range

A relatively stable internal environment, within limits

how does information travel in nervous system communication?

action potential

What activates PKC? A) GTP B) PIP2 C) DAG D)IP3

DAG

Hormones can bind to just one specific cell. T or F

False they can bind to one specific cell or many type of cells

Cleaving ______ to GDP inactives the transducer

GTP

What alpha subunit inhibits adenylyl cyclase?

Gi

activation of phospholipase c β (PLCβ)

Gq

What alpha subunit stimulates adenylyl cyclase?

Gs

Tyrosine kinase can activate _____________ kinase pathway

Mitogen-activated protein (MAP kinase pathway)

NGF

Nerve growth factor

what travel to nearby smooth muscle from endothelial cell causing relaxation of smooth muscle and dilate blood vessels

Nitric oxide (NO)

PLC cleaves PIP2 to DAG (which activates _____________) and IP3 (which opens ____________ channels in ER)

PKC (protein kinases C); Ca++

__________ are released by cells and affect other cell types locally without being transported in blood.

Paracrine chemical signals

If a response enhances the original stimulus, the system is classified as a ______ feedback system.

Positive

Human bodies are able to maintain a certain constancy of their internal environment. This statement A) Refers only to the physiology of the vascular (circulatory) system B) Refers to homeostasis in the body C) Tells how positive feedback mechanisms work D) Refers to the direct control of cell activities by nucleic acids E) is not true in very old or very young humans

Refers to homeostasis in the body

An example of feedback is body temperature regulation. If blood temperature rises too high, this is sensed by specialized neurons in the hypothalamus of the brain. They signal other nerve centers, which in turn send signals to the blood vessels of the skin. As these blood vessels dilate, more blood flows close to the body surface and excess heat radiates from the body. If this is not enough to cool the body back to its set point, the brain activates sweating. Evaporation of sweat from the skin has a strong cooling effect, as we feel when we are sweaty and stand in front of a fan. A. This is a negative feedback loop B. This is not a feedback loop C. This is a positive feedback loop

This is a negative feedback loop

The kidneys sense that the oxygen levels in the blood are low. The kidney sends a hormone signal to the bone marrow to make more red blood cells. The number of red blood cells increases, so more oxygen is carried in the blood. A. This is a negative feedback loop B. This is not a feedback loop C. This is a positive feedback loop

This is a negative feedback loop

Feedback is seen in protein digestion, where the presence of partially digested protein in the stomach triggers the secretion of hydrochloric acid and pepsin, the enzyme that digests protein. Pepsin digests proteins, casing more HCl and pepsin to be released. A. This is a negative feedback loop B. This is not a feedback loop C. This is a positive feedback loop

This is a positive feedback loop

You are eating a hot fudge sundae. The pleasant taste information is sensed by your taste buds, which notify your brain. Your brain releases endorphins, which make you feel very good. You now associate the good feeling with hot fudge sundaes, so you eat another hot fudge sundae. Now you feel even better. Which of the following statements is TRUE regarding this scenario? A) This is a negative feedback loop because two hot fudge sundaes will make you sick. B) This is a positive feedback loop because the results make you feel good. C) This is a negative feedback loop because you were doing something bad for your health in the first place, and the result makes the situation worse. D) This is a positive feedback loop because the stimulus (eating a hot fudge sundae) and the effect (eating another hot fudge sundae) are the same. E) This is a negative feedback loop because the stimulus (eating a hot fudge sundae) and the effect (eating another hot fudge sundae) are the same.

This is a positive feedback loop because the stimulus (eating a hot fudge sundae) and the effect (eating another hot fudge sundae) are the same.

The term homeostasis refers to the maintenance of a relatively stable internal and external environment. (T or F)

True

What type of steroid hormone receptor are soluble and bind DNA upon binding ligand?

Type I

What type of steroid hormone receptors are already bound to DNA and are activated by ligand

Type II

What enzymes can phosphorylate tyrosine residues?

Tyrosine kinases

AC

adenylyl cyclase

What do second messenger system do?

amplification of signal

The type of programmed cell death that is a part is normal development is called

apoptosis

an action potential travels down _________ and ____________ at the end of the neuron

axon; synapse

Which of the following would increase smooth muscle contraction: A. generation of IP3 B. phosphorylation of phospholamban C. hyperpolarization of the sarcolemma D. release of nitric oxide from neighboring cells E. activation of MLC phosphatase

generation of IP3

guanylyl cyclase produces ____________ which targets PKC which _____________ Ca++ causing vasodilation?

cGMP; decreases

what protein causes conformation change from active to inactive form by binding to four Ca++ ions?

calmodulin

The function of adenyl cyclase is to: (a) break down a protein hormone when it binds to its receptor (b) turn on a G-protein (c) cause the conversion of ATP to cAMP (d) activate a protein kinase; inactivate cAMP

cause the conversion of ATP to cAMP

Ca++ pumps create a _______________

concentration gradient

they bring the responses from the brain to the muscles and the glands is called what type of neuron?

efferent or motor

EGF

epidermal growth factor

The endocrine system is quicker than the nervous system. T or F

false

Nervous is __________ and more ___________ than endocrine system

faster; targeted

Homeostasis is maintained primarily via ____________ feedback mechanisms.

negative

Release of many endocrine system hormones is regulated by _______________ .

negative feedback

There is a great overlap in functioning between the endocrine system and the _______________system.

nervous

The two body systems that regulate homeostasis are the

nervous and endocrine systems

Norepinephrine and acetylcholine are examples of which of these types of intercellular chemical signals?

neurotransmitter

guanylyl cyclase is activated by what

nitric oxide

Name the intercellular chemical signal that is released by cells and has a local effect on the same cell type as that from which the chemical signal is released.

paracrine

What type of cell signaling does nitric oxide (NO) use

paracrine

The body senses that substance A is low in the bloodstream. The brain sends a signal to organ B that causes it to make more hormone A until the level of A is within normal limits. A. This is a negative feedback loop B. This is not a feedback loop C. This is a positive feedback loop

this is a negative feedback loop

G protein is a what? A) first messenger B) receptor C) transducer D) effector E) secondary messenger

transducer