Uark physiology exam 2

Which nervous tissue cell functions in immunity in the central nervous system?

Microglia

The specialized junction between two neurons where one neuron alters the electrical and chemical activity of the other is called a

synapse

In a typical neuron which sets of ions are the most important in creating resting membrane potential?

Sodium, Potassium, and Chloride

Which type of neurons form the myelin sheath on neurons in the peripheral nervous system?

Schwann Cells

Which ions are at a higher concentration inside the cell than outside?

K+

Which types of neurons function as an integrator?

interneuron

What type of membrane proteins make a membrane excitable?

gated ion channels

In a typical neuron at rest, what will happen if Na+ ion channels open?

Na+ ions will enter the cell and it will depolarize

What kind of neurons carry sensory information?

afferent neurons

Which region of the brain is responsible for learning, emotional experience, and behavior?

limbic system

Which structure in the brain contains integrating centers for cardiovascular, respiratory, and swallowing functions and is absolutely essential for life?

reticular formation

Which structure in the brain acts as a synaptic relay station for sensory information traveling to the cerebral cortex?

thalamus

Which layer of the meninges contains cerebrospinal fluid?

subarachnoid space

How many neurons are in the pathway from the CNS to a skeletal muscle in the Somatic portion of the Efferent Division of the Peripheral Nervous System?

1

How many neurons are in the pathway between the CNS and an effector in the Autonomic Nervous System?

2

Which division of the Efferent Nervous System is responsible for sending signals that increase the heart rate?

autonomic motor - sympathetic

Which functional branch of the nervous system carries signals to initiate movement of a skeletal muscle?

efferent division - somatic motor

Which portion of the brain is responsible for conscious thought and higher order functions such as reasoning, learning, and memory?

cerebral cortex

Which structure is responsible for producing cerebrospinal fluid?

Choroid plexius

How is the intensity (strong vs. weak) of a stimulus relayed to the central nervous system?

Strong stimuli generate more frequent action potentials.

The type of sensory receptors that detect pain are called...

nociceptors

What sensation is considered Somatic Sensation?

touch

What neurotransmitter is a catecholamine?

Epinephrine

What contains portions of the frontal lobe, thalamus, and hypothalamus and is associated with emotional states such as fear and happiness?

Limbic system

What is the dominant extracellular cation?

Na+

Which part of the brain plays a role in complex processing of incoming sensory information such as integrating information from different senses?

Cortical association areas of the cortex

The resting membrane potential of a neuron is closest to

The equilibrium potential of K+

What part of the nervous system includes the brain and spinal cord?

Central Nervous System

What is responsible for the "fight or flight" response?

Sympathetic Nervous System

The charge difference between the inside and outside of a cell

Membrane potential

Which glial cell produces myelin in the CNS?

Oligodendrocytes

A group of neuronal cell bodies in the CNS is called

Nucleus

If the potassium permeability of a resting neuron increases above the resting permeability, what effect will this have on the membrane potential?

The inside of the membrane will become more negative

The basic unit of the nervous system (nerve cells) are called?

Neurons

What is the resting membrane potential of a typical neuron?

-70mv

White matter is...

myelinated

The depolarization phase of an action potential is caused by

Opening of voltage gated Na+ channels

Which layer of the meninges is thick and next to the bones surrounding the CNS?

Dura Matter

The term saltatory conduction is

Conduction of an action potential along a myelinated axon

What creates the blood-brain barrier?

Tight junctions between the endothelial cells of the CNS capillaries

In a typical cell in the human body, how does the change inside a cell compare to that outside the cell?

The inside of a cell is negative relative to the outside

Fibers that originate from the different parts of the nervous system and lead to the same neuron are exhibiting

Convergence

The sympathetic nervous system is responsible for

Fight or flight

Which term does NOT belong with the others?

A) CNS
B) spinal cord
C) brain
D) spinal nerve

D) spinal nerve

Which of the below terms does NOT belong with the others?

A) spinal nerve
B) cranial nerve
C) PNS
D) spinal cord

D) spinal cord

Select the INCORRECT statement about nerve impulse conduction.

A) The neuron cannot be stimulated during the absolute refractory period.
B) The strength of impulses carried along a single nerve fiber can vary with the strength of their stimulus.
C) Nerve impulses occurs in an all-or-none matter.
D) Saltatory conduction involves Schwann cells and occurs at greater speed than on unmyelinated fibers

B) The strength of impulses carried along a single nerve fiber can vary with the strength of their stimulus.

Which of the following statements about the action potential is FALSE?

A) The rapid depolarization phase is caused by the entry of potassium ions.
B) During the depolarization phase, membrane potential becomes positive.
C) During the repolarization phase, sodium channels close and potassium channels open.
D) None of these statements is false - all are true.

A) The rapid depolarization phase is caused by the entry of potassium ions.

They can be depolarizations or hyperpolarizations that can vary in magnitude.

graded potentials

Movement of molecules from one location to another solely as a result of their random thermal motion. (Random movement from high to low concentration)

Simple diffusion

What types of molecules can pass through a lipid bilayer?

Polar substances and ions (water, Na+, Ca2+, and Glucose) cannot pass through, while non-polar substances (carbon dioxide, oxygen, lipids, and steroids) can.

The direction and magnitude of ion fluxes across the membranes depend on both the concentration differences and the electrical difference.

Electrochemical gradient

How is movement through channels regulated?

Regulated through ligand-gated channels, voltage gated channels, and mechanically gated channels

Uses a transporter to move the solute from higher to lower concentration

Facilitated diffusion

Active transport in which chemical energy is transferred directly from ATP to transporter protein.

Primary active transport

Active transport in which energy is released during transmembrane movement of one substance from higher to lower concentration is transferred to the simultaneous movement of another substance from lower to higher concentration.

Secondary active transport

Movement of the actively transported solute into the cell.

Cotransport (symporter)

Movement of the actively transported solute out of the cell.

Counter transport (antiporter)

Diffusion of water molecules through a semi-permeable membrane. Water moves from an area of high concentration to an area of low concentration through aquaporins.

Osmosis

Total solute concentration of a solution.

Osmolarity

No change in cell volume, the concentration are in equilibrium (equal inside and outside the cell).

Isotonic

The cell swells, the concentration of water inside the cell is less than the outside of the cell causing water to move into the cell causing it to swell and maybe burst.

Hypotonic

The cell shrinks, the concentration of water inside the cell is greater than outside the cell making the water move out of the cell causing it to shrink.

Hypertonic

Membrane-bound vesicles in the cytoplasm fuse with the plasma membrane and release their contents to the outside of the cell.

Exocytosis

Regions of the plasma membrane can often be seen to have folded into the cell, forming small pockets that pinch off to produce intracellular, membrane-bound vesicles that enclose a small volume of extracellular fluid.

Endocytosis

Extracellular fluid is taken into the cell.

Pinocytosis

Cells engulf bacteria or large particles such as cell debris from damaged tissue.

Phagocytosis

Certain molecules in the extracellular fluid bind to specific proteins on the outer surface of the plasma membrane.

Receptor-mediated endocytosis

Diffusion occurs between the adjacent cells of the epithelium.

Paracellular Pathway

A substance moves into an epithelial cell across either the apical or basolateral membrane, diffuses through the cytosol, and exits across the opposite membrane.

Transcellular pathway

Specific target cell receptors for chemical messengers.

Receptors (Proteins)

A sequence of events in the cell leading to the cell's response to the messenger.

Signal Transduction

The ability of a receptor to bind only one type or a limited number of structurally related types of chemical messengers.

Specificity

The degree to which receptors are occupied by messengers. If all are occupied, the receptors are fully saturated; if half are occupied, the saturation is 50% , and so on.

Saturation

The strength with which a chemical messenger binds to its receptor.

Affinity

The ability of different molecules to compete with a ligand for binding to its receptor. Competitors generally are similar in structure to the natural ligand.

Competition

A molecule that competes with a ligand for binding to its receptor but does not activate signaling normally associated with the natural ligand. Prevents actions of the natural ligand.

Antagonist

A chemical messenger that binds to a receptor and triggers the cell's response; often refers to a drug that mimics a normal messenger's action.

Agonist

The diverse sequences of events that link receptor activation to cellular responses.

Signal Transduction Pathways

Found on the plasma membrane, in the cytosol, and also in the nucleus of the target cell. They are generally intracellular receptors and initiate signal transduction for steroid hormones.

Steroid-Hormone Receptor

The first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase.

Transcription

Pathway initiated by lipid-soluble messengers

Intracellular

Pathways initiated by water-soluble messengers

Extracellular

Plasma membrane receptors for water-soluble messengers:

1) Receptors that are ligand-gated channels.
2) Receptors that themselves function as enzymes, such as receptor tyrosine kinases
3) Receptors that are bound to and activate cytoplasmic janus kinases
4) G-protein-Coupled receptors that activate G proteins, which in turn act upon effector proteins\---either ion channels or enzymes\---in the plasma membrane.

The name for and enzyme that phosphorylates other proteins by transferring a phosphate group to them from ATP.

Protein Kinase

A group of transmembrane ion channel proteins which open to allow ions such as Na+, K+, Ca2+, or Cl- to pass through the membrane in response to the binding of a chemical messenger (i.e. a ligand) such as a neurotransmitter,

Ligand gated ion channel

Consists of the nerves that connect the brain and spinal cord with he body's muscles, glands, sense organs, and other tissues

Peripheral Nervous System (PNS)

Contains the nucleus and ribosomes and has the genetic info and machinery necessary for protein synthesis

Cell Body (soma)

Highly branched outgrowths of the cell body. They receive incoming sensory info and transfer it to integrating regions.

Dendrites

Process that extends from the cell body and carries outgoing signals to its target cells

Axon

Trigger zone where signals are generated

Axon Hillcock

Responsible for releasing neurotransmitters from the axon.

Axon terminal

Convey info from the tissues and organs of the body toward the CNS

Afferent Neurons

Convey info way from the CNS to effector cells like muscle, gland

Efferent Neurons

Noneuronal cell in CNS; helps regulate extracellular environment of CNS, also called neurolgia

glial cells

Insulating material covering axons of many neurons; consists of layers of myelin forming cell plasma membrane wrapped around axon

Myelin

Fluid that fills cerebral ventricles and the subarachnoid space surrounding the brain and spinal cord

Cerebralspinal fluid

To change membrane potential value toward zero so that cell interior becomes less negative than resisting potential

Depolarized

To change membrane potential so cell interior becomes more negative than its resting state

Hyperpolarized

Return transmembrane potential to its resting level

Repolarized

Time during which excitable membrane will produce action potential but only to a stimulus of greater strength than the usual threshold strength

relative refractory period