Cell Communication, Endocrine system, and Nervous System

cyclic AMP

(cAMP) cyclic adenosine monophosphate, a ring shaped molecule made from ATP that is a common intercellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons

glial cells

(glia) cells of the nervous system that support, regulate, and augment the functions of neurons

corticosteriods

Any steroid hormones produced and secreted by the adrenal cortex

G protein

GTP binding protein that relays signals from a plasma membrane signal receptor to other signal transduction proteins inside the cell

norepinephrine

a catecholamine that is chemically and functionally similar to epinephrine and acts as a hormone or neurotransmitter; also known as noradenaline

epinephrine

a catecholamine that, when secreted as a hormone by the adrenal medulla, mediates "fight or flight" responses to short-term stresses; also released by some neurons as a neurotransmitter; also known as adrenaline

G protein coupled receptor

a cell-surface transmembrane receptor that works with the help of a G protein

hyperpolarization

a change in a cell's membrane potential such that the inside of the membrane becomes more negative relative to the outside. Hyperpolarization reduces the chance that a neuron will transmit a nerve impulse

depolarization

a change in a cell's membrane potential such that the inside of the membrane is made less negative relative to the outside . For example, a neuron membrane is depolarized if a stimulus decreases its voltage from the resting potential of -70 mV in the direction of zero voltage

brain stem

a collection of structures in the vertebrate brain, including the midbrain, the pons, and the medulla oblongata; functions in homeostasis, coordination of movement, and conduction of information to higher brain centers

nerve

a fiber composed primarily of the bundled axons of PNS neurons

nitric oxide (NO)

a gas produced by many types of cells that functions as a local regulator and as a neurotransmitter

gated ion channels

a gated channel for a specific ion. The opening or closing of such channels may alter a cell's membrane potential

pancreas

a gland with exocrine and endocrine tissues. The exocrine portion functions in digestion, secreting enzymes and an alkaline solution into the small intestine via a duct; the ductless endocrine portions functions in homeostasis, secreting the hormones insulin and glucagon into the blood.

Melanocyte-stimulating hormone (MSH)

a hormone produced and secreted by the anterior pituitary with multiple activities, including regulating the behavior of pigment containing cells in the skin of some vertebrates

calcitonin

a hormone secreted by thyroid gland that lowers blood calcium levels by promoting calcium deposition in bone and calcium excretion from the kidneys; nonessential in adult humans

tropic hormone

a hormone that has an endocrine gland or cells as the target

growth factors

a local regulator that acts on nearby cells to stimulate cell proliferation and differentiation

ligand

a molecule that specifically binds to another molecule, often a larger one

neurohormone

a molecule that's secreted by a neuron, travels in body fluids, and acts on specific target cells, changing their functioning

sensory neurons

a nerve cell that receives information from the internal or external environment and transmits signals to the central nervous system

motor neurons

a nerve cell that transmits signals from the brain or spinal cord to muscles or glands

biogenetic amine

a neurotransmitter derived from an amino acid

dopamine

a neurotransmitter that is a catecholamine, like epinephrine and norepinephrine

serotonin

a neurotransmitter, synthesized from the amino acid tryptophan, that functions in the central nervous system

temporal summation

a phenomenon of neural integration in which the membrane potential of the postsynaptic cell in a chemical synapse is determined by the combined effect of EPSPs or IPSPs produced in rapid succession

spatial summation

a phenomenon of neural integration in which the membrane potential of the postsynaptic cell is determined by the combined effect of EPSPs or IPSPs produced nearly simultaneously by different synapses

pons

a portion of the brain that participates in certain automatic, homeostatic function, such as regulating the breathing centers in the medulla

Receptor tyrosine kinase

a receptor protein spanning the plasma membrane that often responds to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins on the cell

neuropeptide

a relatively short chain of amino acids that serves as a neurotransmitter

Diacylglycerol (DAG)

a second messenger produced by the cleavage of the phospholipid PIP2 in the plasma membrane

Inositol triphosphate (IP3)

a second messenger that functions as an intermediate between certain signaling molecules and a subsequent second messenger, Ca2+, by causing rise in cytoplasmic Ca2+ concentration

local regulators

a secreted molecule that influences cells near where it is secreted (ex: paracrine signaling, synaptic signaling)

Phosphorylation cascade

a series of different molecules in a pathway are phosphorylated in turn, each molecule adding a phosphate group to the next one in line

voltage-gated ion channels

a specialized ion channel that opens or closes in response to changes in membrane potential

testosterone

a steroid hormone required for development of the male reproductive system, spermatogenesis, and male secondary sex characteristics; the major androgen in mammals

progesterone

a steroid hormone that prepares the uterus for pregnancy; the major progestin in mammals

Estradiol

a steroid hormone that stimulates the development and maintenance of the female reproductive system and secondary sex characteristics; the major estrogen in mammals

ion channels

a transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient

Ligand-gated ion channel

a transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor

luteinizing hormone (LH)

a tropic hormone that is produced and secreted by the anterior pituitary and that stimulates ovulation in females and androgen production in males

follicle-stimulating hormone (FSH)

a tropic hormone that is produced and secreted by the anterior pituitary and that stimulates the production of eggs by the ovaries and sperm by the testes

axon

a typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells

The relationship between the insect hormones ecdysteroid and PTTH is an example of a. an interaction of the endocrine and nervous systems b. homeostasis achieved by positive feedback c. how peptide derived hormones have more widespread effects than steroid hormones d. homeostasis maintained by antagonistic hormones e. competitive inhibition of a hormone receptor

a. an interaction of the endocrine and nervous systems

Consider this pathway: epinephrine→ G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger. a. cAMP b. G protein c. GTP d. adenylyl cyclase e. G protein-coupled receptor

a. cAMP

The activation of receptor tyrosine kinases is characterized by a. dimerization and phosphorylation b. dimerization and IP3 binding c. a phosphate cascade d. GTP hydrolysis e. channel protein shape change

a. dimerization and phosphorylation

Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal? a. high insulin, low glucagon b. low insulin, low glucagon c. high insulin, high glucagon d. low insulin, high glycogen e. low insulin, no change in glucagon

a. high insulin, low glucagon

Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal? a. voltage gated calcium channels in the membrane open b. synaptic vesicles fuse with the membrane c. the postsynaptic cell produces an action potential d. ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft e. an EPSP or IPSP is generated in the postsynaptic cell

a. voltage gated calcium channels in the membrane open

Quorum sensing

allows bacterial populations to coordinate their behaviors so they can carry out activities that are only productive when performed by a given number of cells in synchrony

biofilm

an aggression of bacterial cells adhered to a surface; the cells in a biofilm generally derive nutrition from the surface they are on

gamma-aminobutyric acid (GABA)

an amino acid that functions as a CNS neurotransmitter in the central nervous system of vertebrates

glutamate

an amino acid that functions as a neurotransmitter in the central nervous system

interneurons

an association neuron; a nerve cell within the central nervous system that forms synapses with sensory and/or motor neurons and integrates sensory input and motor output.

excitatory postsynaptic potential (EPSP)

an electrical change (depolarization) in the membrane of a postsynaptic cell caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more likely for a postsynaptic cell to generate an action potential

inhibitory postsynaptic potential (IPSP)

an electrical charge (usually hyper polarization) in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes in more difficult for a postsynaptic neuron to generate an action potential

action potential

an electrical signal that propagates along the membrane of a neuron or other excitable cell as a nongraded (all-or-none) depolarization

diabetes mellitus

an endocrine disorder marked by an inability to maintain glucose homeostasis. The type 1 form results from autoimmune destruction of insulin-secreting cells; treatment usually requires daily insulin injections. The type 2 form most commonly results from reduced responsiveness of target cells to insulin; obesity and lack of exercise are risk factors.

pituitary gland

an endocrine gland at the base of the hypothalamus; consists of a posterior lobe, which stores and releases two hormones produced by the hypothalamus, and an anterior lobe, which produces and secretes many hormones that regulate diverse body functions

thyroid gland

an endocrine gland, located on the ventral surface of the trachea, the secretes two iodine-containing hormones, triiodothyronine (T3) and thyroxine (T4), as well as calcitonin

Kinase

an enzyme that catalyzes the transfer of phosphate groups

Protein kinase

an enzyme that transfers phosphate groups from ATP to protein

posterior pituitary

an extension of the hypothalamus composed of nervous tissue that secretes oxytocin and antidiuretic hormone made in the hypothalamus; a temporary storage site for these hormones

thalamus

an integrating center of the vertebrate forebrain. Neurons with cell bodies in the thalamus relay neural input to specific areas in the cerebral cortex and regulate what information goes to the cerebral cortex

catecholamine

any of a class of neurotransmitters and hormones, including the hormones epinephrine and norepinephrine, that are synthesized from the amino acid tyrosine

endorphine

any of several hormones produced in the brain and anterior pituitary that inhibit pain perception

Estrogen

any steroid hormone that stimulates the development and maintenance of the female reproductive system and secondary sex characteristics

progestin

any steroid hormone with progesterone-like activity

androgen

any steroid hormone, such as testosterone, that stimulates the development and maintenance of the male reproductive system and secondary sex characteristics

Apoptosis involves all but which of the following? a. fragmentation of the DNA b. cell-signaling pathways c. activation of cellular enzymes d. lysis of the cell e. digestion of cellular contents by scavenger cells

b. cell-signaling pathways

Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal? a. greater production of T3 than T4 b. hypo secretion of TSH c. hyper secretion of TSH d. hyper secretion of MSH e. a decrease in the thyroid secretion of calcitonin

b. hypo secretion of TSH

An example of antagonistic hormones controlling homeostasis is a. thyroxine and parathyroid hormone in calcium balance b. insulin and glucagon in glucose metabolism c. progestins and estrogens in sexual differentiation d. epinephrine and norepinephrine in fight or flight responses e. oxytocin and prolactin in milk production

b. insulin and glucagon is glucose metabolism

Lipid-soluble signaling molecules, such as testosterone, cross the membrane of all cells but affect only target cells because a. only target cells retain the appropriate DNA segments b. intracellular receptors are present only in target cells c. most cells lack the Y chromosome required d. only target cells possess the cytosolic enzymes that transduce the testosterone e. only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor

b. intracellular receptors are present only in target cells

Why are action potentials usually conducted in one direction? a. the nodes of Ranvier conduct potentials in one direction b. the brief refractory period prevents reopening of voltage gated Na+ channels c. the axon hillock has a higher membrane potential than the terminals of the axon d. ions can flow along the axon in only one direction e. voltage gated channels for both Na+ and K+ open in only one direction

b. the brief refractory period prevents reopening of voltage gated Na+ channels

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because a. they are species specific b. they always lead to the same cellular response c. they amplify the original signal manyfold d. they counter the harmful effects of phosphatases e. the number of molecules used is small and fixed

c. The amplify the original signal manyfold

Protein phosphorylation is commonly involved with all of the following except a. regulation of transcription by extracellular signaling molecules b. enzyme activation c. activation of G protein-coupled receptors d. activation of receptor tyrosine kinases e. activation of protein kinase molecules

c. activation of G protein-coupled receptors

A common feature of action potentials is that they a. cause the membrane to hyperpolarize and then depolarize b. can undergo temporal and spatial summation c. are triggered by a depolarization that reaches the threshold d. move at the same speed along all axons e. require the diffusion of Na+ and K+ through ligand-gated channels to propagate

c. are triggered by a depolarization that reaches the threshold

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? a. enzymatic activity was proportional to the amount of calcium added to a cell-free extract b. receptor studies indicated that epinephrine was a ligand c. glycogen breakdown was observed only when epinephrine was administered to intact cells d. glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined e. epinephrine was known to have different effects on different types of cells

c. glycogen breakdown was observed only when epinephrine was administered to intact cells

Which of the following is not an accurate statement? a. Hormones are chemical messengers that travel to target cells through the circulatory system b. hormones often regulate homeostasis through antagonistic functions c. hormones of the same chemical class usually have the same function d. hormones are secreted by specialized cells usually located in endocrine glands e. hormones are often regulated through feedback loops

c. hormones of the same chemical class usually have the same function

Which hormone is incorrectly paired with its action a. oxytocin-stimulates uterine contractions during childbirth b. thyroxine-stimulates metabolic processes c. insulin-stimulates glycogen breakdown in the liver d. ACTH- stimulates the release of the glucocorticoids by the adrenal cortex e. melatonin-affects biological rhythms, seasonal reproduction

c. insulin-stimulates glycogen breakdown in the liver

What happens when a resting neuron's membrane depolarizes? a. there is a net diffusion of Na+ out of the cell b. the equilibrium potential for K+ (Ek) becomes more positive c. the neuron's membrane voltage becomes more positive d. the neuron is less likely to generate an action potential e. the cell's inside is more negative than the outside

c. the neuron's membrane voltage becomes more positive

Where are neurotransmitter receptors located? a. the nuclear membrane b. the nodes of Ranvier c. the postsynaptic membrane d. synaptic vesicle membranes e. the myelin sheath

c. the postsynaptic membrane

Steroid and peptide hormones typically have in common a. the building blocks from which they are synthesized b. their solubility in cell membranes c. their requirement for travel through the bloodstream d. the location of their receptors e. their reliance on signal transduction in the cell

c. their requirement for travel through the bloodstream

Pheromones

chemicals that are released into the external environment

hormones

chemicals used for long-distance signaling (endocrine signaling)

ganglia

clusters of nerve cell bodies in a centralized nervous system

Transduction

converts the signal to a form that can bring about a specific cellular response

Growth factors are local regulators that a. are produced by the anterior pituitary b. are modified fatty acids that stimulate bone and cartilage growth c. are found on the surface of cancer cells and stimulate abnormal cell division d. bind to cell-surface receptors and stimulate growth and development of target cells e. convey messages between nerve cells

d. bind to surface-receptors and stimulate growth and development of target cells

Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane? a. receptor tyrosine kinase b. G protein-coupled receptor c. phosphorylated receptor tyrosine kinase dimer d. ligand-gated ion channel e. intracellular receptor

d. ligand-gated ion channel

endocrine glands

ductless glands that secrete hormones directly into the interstitial fluid, from which they diffuse into the bloodstream

Temporal summation always involves a. both inhibitory and excitatory inputs b. synapses at more than one site c. inputs that are not simultaneous d. electrical synapses e. multiple inputs at a single synapse

e. multiple inputs at a single synapse

Adenylyl cyclase

enzyme embedded in the plasma membrane converts ATP to cAMP in response to an extracellular signal (provided by epinephrine)

Protein phosphatases

enzymes that can rapidly remove phosphate groups from proteins, a process called dephosphorylation

negative feedback

form of regulation in which accumulation of an end product of a process slows the process; in physiology, a primary mechanism of homeostasis, whereby a change in a variable triggers a response that counteracts the initial change

positive feedback

form of regulation in which an end product of a process speeds up that process; in physiology, a control mechanism in which a change in a variable triggers a response that reinforces or amplifies the change.

nodes of Ranvier

gap in the myelin sheath of certain axons where an action potential may be generated. In saltatory conduction, an action potential is regenerated at each node, appearing to "jump" along the axon from node to node

diencephalon

gives rise to the hypothalamus, thalamus, and epithalamus. Sends sensory and motor information to the cerebrum; regulates homeostasis

prostaglandins

group of modified fatty acids secreted by virtually all tissues and performing a wide variety of functions as local regulators

prolactin

hormone produced and secreted by the anterior pituitary with a great diversity of effects in different vertebrate species. In mammals, it stimulates growth of and milk production by the mammary glands

oxytocin

hormone produced by the hypothalamus and released from the posterior pituitary. It induces contractions of the uterine muscles during labor and causes the mammary glands to eject milk during nursing.

glucagon

hormone secreted by pancreatic alpha cells that raises blood glucose levels. It promotes glycogen breakdown and release of glucose by the liver.

insulin

hormone secreted by pancreatic beta cells that lowers blood glucose levels. It promotes the uptake of glucose by most body cells and the synthesis and storage of glycogen in the liver and also stimulates protein and fat synthesis.

parathyroid hormone (PTH)

hormone secreted by the parathyroid glands that raises blood calcium level by promoting calcium release from bone and calcium retention by the kidneys

Growth hormone (GH)

hormone that is produced and secreted by the anterior pituitary and that has both direct (non tropic) and tropic effects on a wide variety of tissues

melatonin

hormone that is secreted by the pineal gland and that is involved in the regulation of biological rhythms and sleep

graded potential

in a neuron, a shift in the membrane potential that has an amplitude proportional to signal strength and that decays as it spreads

epithalamus

includes the pineal gland, the source of melatonin as well as one of several clusters of capillaries that generate cerebrospinal fluid from blood

Voltage gated ion channels

ion channels gated by electrical signals instead of ligands

Scaffolding proteins

large relay proteins to which several other relay proteins are simultaneously attached; increase the efficiency of signal transduction

neurotransmitters

molecule that is released from the synaptic terminal of the a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to the postsynaptic cell, triggering a response

neuron

nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its plasma membrane

parathyroid gland

one of four small endocrine glands, embedded in the surface of the thyroid gland, that secrete parathyroid hormone

acetylcholine

one of the most common neurotransmitters; functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions, either depolarizing or hyperpolarizing the membrane

midbrain

one of three ancestral and embryonic regions of the vertebrate brain; develops into sensory integrating and relay centers that send sensory information to the cerebrum

adrenal gland

one of two endocrine glands located adjacent to the kidneys in mammals. Endocrine cells in the outer portion respond to adrenocorticotropic hormone by secreting steroid hormones that help maintain homeostasis during long-term stress. Neurosecretory cells in the central portion secrete epinephrine and norepinephrine in response to nerve signals triggered by short term stress.

Thyroxine (T4)

one of two iodine containing hormones that are secreted by the thyroid gland and that help regulate metabolism, development, and maturation in vertebrates

Triiodothyronine (T3)

one of two iodine containing hormones that are secreted by the thyroid gland and that help regulate metabolism, development, and maturation in vertebrates

dendrite

one of usually numerous, short, highly branched extensions of a neuron that receive signals from other neurons

brain

organ of the central nervous system where information is processed and integrated

cerebellum

part of the vertebrate hindbrain located located dorsally; functions in unconscious coordination of movement and balance

antidiuretic hormone (ADH)

peptide hormone, also known as vasopressin, the promotes water retention by the kidneys. Produced in the hypothalamus and released from the posterior pituitary, ADH also functions in the brain

anterior pituitary

portion of the pituitary that develops from non-neural tissue; consists of endocrine cells that synthesize and secrete several tropic and non tropic hormones

saltatory conduction

rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin sheath regions of membrane

Signal transduction pathway

series of steps (reception, transduction, response) that convert a received signal to a specific cellular response

pineal gland

small gland on the dorsal surface of the vertebrate forebrain that secretes the hormone melatonin

Second messengers

small, non-protein, water soluble molecules or ions involved in many signaling pathways

Ecdysteroid

steroid hormone, secreted by the prothoracic glands, that triggers molting in arthropods

glucocorticoids

steroid hormones that are secreted by the adrenal cortex and that influence glucose metabolism and immune function

Reception

target cell's detection of a signaling molecule coming from outside the cell

paracrine signaling

target cells lie near the secreting cell

membrane potential

the difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions. Membranes potential affects the activity of excitable cells and the transmembrane movement of all charged substances

cerebrum

the dorsal portion of the vertebrate forebrain, composed of right and left hemispheres; the integrating center for memory, learning, emotions, and other highly complex functions of the central nervous system

endocrine system

the internal system of communication involving hormones, the ductless glands that secrete hormones, and the molecular receptors on or in target cells that respond to hormones; functions in concert with the nervous system to effect internal regulation and maintain homeostasis

synapse

the junction where a neuron communicates with another cell across a narrow gap via a neurotransmitter or an electrical coupling

signal transduction

the linkage of a mechanical, chemical, or electromagnetic stimulus to a specific cellular response

medula oblongata

the lowest part of the vertebrate brain, commonly called the medulla; a swelling of the hindbrain anterior to the spinal cord that controls autonomic, homeostatic functions, including breathing, heart and blood vessel activity, swallowing, digestion, and vomiting

equilibrium potential (Eion)

the magnitude of a cell's membrane voltage at equilibrium; calculated using the Nernst equation

resting potential

the membrane potential characteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside

cell body

the part of the neuron that houses the nucleus and most other organelles

central nervous system (CNS)

the portion of the nervous system where signal integration occurs; in vertebrate animals, the brain and spinal cord

threshold

the potential that an excitable cell membrane must reach for an action potential to be initiated

peripheral nervous system (PNS)

the sensory and motor neurons that connect to the central nervous system

refractory period

the short time immediately after an action potential in which the neuron cannot respond to another stimulus, owing to the inactivation of voltage-gated sodium channels

autocrine signaling

the target cell is the secreting cell itself

corpus callosum

the thick band of nerve fibers that connects the right and left cerebral hemispheres to process information together

Response

the transducer signal triggers a specific cellular response

hypothalamus

the ventral part of the vertebrate forebrain; functions in maintaining homeostasis, especially in coordinating the endocrine and nervous systems; secretes hormones of the posterior pituitary and releasing factors that regulate the anterior pituitary

adrenocorticotropic hormone (ACTH)

tropic hormone that is produced and secreted by the anterior pituitary and that stimulates the production and secretion of steroid hormones by the adrenal cortex

oligodendrocyte

type of glial cell that forms insulating myelin sheaths around the axons of neurons in the central nervous system

Schwann cell

type of glial cell that forms insulating myelin sheaths around the axons of neurons in the peripheral nervous system

Apoptosis

type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell

myelin sheath

wrapped around the axon of a neuron, an insulating coat of cell membrane from Schwann cells or oligodendrocytes. It is interrupted by nodes of Ranvier, where action potentials are generated