Exam 2

Which type of chemical messenger, when released, binds to receptors on the cell that released the chemical messenger?

Autocrine

An intercellular junction that allows for direct passage of ions between two neighboring cells is called

Gap junction

Parathyroid hormone does all of the following except that it

Increases GI losses of Ca ++

Binding of the extra cellular chemical messenger to the receptor can cause which of the following reaction(s) in the cell

Initiate of translation, cell shape changes, activation of cellular enzymes

Receptors for lipid soluble chemical messengers are primarily located

Inside the cell

The secretion of parathyroid hormone is controlled by the concentration of

Ionized calcium in the blood

If I can block neurotransmitters attaching to chemically-gated sodium channels, what will be the result?

An action potential will not be produced

The junction between a stimulating neuron and the next neuron or muscle fiber is known as a(n)

Synapse

Cells affected by hormones are known as

Target cells

Which of the following chemical messenger is NOT derived from an amino acid?

Testosterone

During downregulation of a hormone response

The number of receptors decreases

During up regulation of a hormone response

The number of receptors increased

The electrical balance of the membrane potential can be changed from its resting potential by

The opening of ion channels

A example of a negative feedback loop would be

The release of glucagon in response to low blood sugar

A example of a positive feedback loop would be

The release of oxytocin in response to stretching of the uterus

When a hormone attaches to a receptor on the outside of the cell a second messenger mechanism is activated with results in an "enzyme cascade" which means

The second messenger causes the activation of many enzymes which activate even more enzymes

What results in the depolarization of the cell membrane?

Voltage-gated sodium channels open allowing sodium ions to enter the cell to cancel negative charges on the inside of the membrane

The primary function of ADH is to

Water absorption

The type of channel that only opens when neurotransmitter attaches to its associated receptor is known as a

a chemically gated channel

The differences in electrical charges on either side of the cell membrane results in what is referred to as

membrane potential

A change in the electrical state of the cell membrane which causes a response in the next cell is known as a(n)

Action potential

Ligands that mimic the natural biological response when they bind to a receptor are known as

Agonists

It is a well-known fact that alcohol has a dehydrating effect on the body. What is the mechanism behind the effect?

Alcohol inhibits ADH production by hypothalamus neurons

Reduced fluid losses in the urine due to retention of sodium ions and water is a result of the action of

Aldosterone

The principle that states that a stimulus either causes an action potential or does not cause an action potential is known as the

All-or-none principle

Cytokines secreted by cancer cells that increase cancer growth are an example of which type of signaling?

Autocrine

TSH levels in blood are often used by doctors to adjust doses of thyroid hormone replacement medications such as Synthroid. Why is TSH a good indicator of circulating thyroid hormone levels

Because TSH is negatively regulated by thyroxine levels

Endogenous extracellular molecules X and Y both bind to a receptor on the target cell. Binding of molecule X to the receptor results in changes in the cells behavior. Binding of molecule Y does not result in changes in the cells behavior. Which molecules can be called the ligand?

Both molecules X and Y

The anterior pituitary is regulated

By hormones from the hypothalamus

What ion must flow into the presynaptic cell in order for it to release neurotransmitter?

Calcium

Hydrophobic hormones are derived from

Cholesterol

receptor antagonists are often used as drugs to block the response caused by an internal natural ligand. What property of receptors could these drugs rely on?

Competitive binding

The strength of the cells response to hormonal stimulation is determined by

Concentration of the hormone in blood

When the inside of the membrane becomes less negative, the membrane potential is said to be

Depolarized

Testosterone has which of the following properties or mechanisms of action?

Diffuses into the cell before binding to its receptor

Which of the following would be used to send information concerning the smell of freshly baked bread to multiple regions of the brain

Diverging circuits

ACTH is a hormone that is released from the anterior pituitary gland that increases the production and release of cortisol from adrenal glands. What type of signaling is ACTH to adrenal gland classified as?

Endocrine signaling

Some hormones exhibit synergistic or antagonistic effects on each other. Which of the hormones below do you think exhibit synergy on blood sugar levels

Epinephrine and glucagon

The adrenal medulla produces the hormones

Epinephrine and norepinephrine

Which of the following is the example of cell to cell signaling

Exciting a muscle fiber by motor neuron

Which one of the hormones listed below is NOT produced by the anterior pituitary?

Gonadotropin-releasing hormone

What levels of TSH in blood would you expect in a person after a total thyroidectomy (removal of thyroid) before hormone therapy has started?

High

Which of the following classes of chemical messengers travels in the bloodstream to the target cell?

Hormone only

Chemicals produced by endocrine cells reach their intended recipients by traveling through the bloodstream

Hormones

The type of hormone, such as a steroid, which passes directly through the cell membrane to nuclear receptors to cause changes in gene expression within the cell are known as

Hydrophobic hormones

antidiuretic hormone (ADH) is synthesized in the

Hypothalamus

Which of the following anterior pituitary hormone stimulates the gonads to secrete progesterone in females or testosterone in males

Luteinizing hormone

The inhibition off thyroid-stimulating hormone (TSH) secretion by an increased blood concentration of thyroid hormone is an example of

Negative feedback

Which type of chemical messenger is released from the axon terminals of a neutron and directly communicates with other cells

Neurotransmitters

The drugs called beta blockers are competitive antagonists often hated in medicine to prevent epinephrine from binding to beta adrenergic receptors and in turn leading to decrease of blood pressure and heart rate. When the beta blockers are used in the patient they change

Numbers of receptors bound to epinephrine

Which type of signaling involves chemical messengers working on other cells in the immediate neighborhood of secretory cell

Paracrine

The adrenal Cortex

Produces steroid hormones

Which of the following chemical messenger is lipophilic

Prostaglandin

A type of membrane transport protein that uses ATP to move ions against their concentration gradient is known as

Pump

Hormones which cannot pass through the cell membrane must attach to __ on the cell surface to affect the cell

Receptors

Endocrine cells

Release their secretions directly into the blood stream

In chemical communications between cells, a ___ cell secretes a chemical messenger that binds to ___ on the ___ cell

Secretory; receptors; Target

What is the most common method of communication between cells in animal bodies

Securing chemical messengers that attach to target cells

Parathyroid hormone works by several mechanisms to maintain an adequate level of calcium in the blood. Which of the following is a mechanism of parathyroid hormone action?

Stimulates release of calcitriol

anterior pituitary

adenohypophysis

Interleukins and interferons are examples of ________ released from white blood cells.

cytokine

Movement of ions through an open channel is due to

diffusion

Direct communication between cells in contact with one another is accomplished through

gap junctions

Alpha cells are to ________ as beta cells are to ________.

glucagon and insulin

Which type of chemical messenger is released into the bloodstream by an endocrine gland where it can affect target cells throughout the body?

hormone

When hormones attach to nuclear receptors, the general result is

synthesis of new proteins

Some voltage-gated channels do not allow ions to pass through when their activation gate is open because

there is a second gate, an inactivation gate, that closes to block the channel.

If the accumulation of graded potentials in the trigger zone reaches threshold, the result is

voltage gated channels open