Chapter 3

Question 1

Dendritic Tree

Answer 1

Refers to the branching out of the nerve fibers at the end of a neuron. The dendrites receive neural impulses from axons of other neurons

Question 2

Postsynaptic receptor

Answer 2

Any receptor located on the cell membrane or in the interior of a postsynaptic neuron

Question 3

Postsynaptic

Answer 3

Of, occurring in, or being a nerve cell by which wave of excitation is conveyed away from a synapse

Question 4

Presynaptic

Answer 4

Relating to or denoting a nerve cell that releases a transmitter into a synapse during transmission of an impulse

Question 5

Action Potentials

Answer 5

A temporary shift in the bruins membrane potential caused by ions suddenly flowing in and out of the neuron

Question 6

Myelin Sheath

Answer 6

Speeds up a signal transmission along the axon, and protects

Question 7

Dendrites

Answer 7

Receive signals from neighboring neurons

Question 8

Axon Terminals

Answer 8

Any of the button like endings of axons through which axons make synaptic contacts with other nerve cells or effector cells. Synaptic vesicles containing neurotransmitters are docked. Transmit signals to other neuron dendrites or tissues

Question 9

Synapse

Answer 9

A junction between 2 nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter

Question 10

Synaptic Cleft

Answer 10

Space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter

Question 11

Photoreceptors

Answer 11

Cells in the retina that respond to light. Presence of large amounts of tightly packed membrane that contains the photopigment rhodopsin or a related molecule

Question 12

Somatosensory Receptor

Answer 12

Detect changes either in the environment or within the body

Question 13

Ionotropic receptor

Answer 13

Ligant-gated ion channel. Membrane bound receptor proteins that respond to ligand binding by opening an ion channel and allowing ions to flow into the cell, either increasing or decreasing the likelihood that an action potential will fire fast synaptic transmission

Question 14

metabotropic receptors

Answer 14

Large monometric transmembrane proteins containing seven-transmemebrane domains that initiate intracellular signaling via coupling to G proteins. Neurotransmitter binding triggers a signaling pathway which may indirectly open or close channels

Question 15

Somatostatin

Answer 15

Found primarily in neurons and digestive systems. Prevent production of other hormones and stop the unnatural rapid reproduction of cells. Acts as a neurotransmitter

Question 16

Substance P

Answer 16

An undecapeptide that derives from alpha, beta, and gamma pre-protachykinin gene transcription and is a neurotransmitter or neuromodulator of primary nociceptive afferents

Question 17

Enkephalins

Answer 17

Endogenous opioid pentapeptides that are produced mainly in the CNS, adrenal medulla, and other peripheral tissues

Question 18

Catecholamines

Answer 18

Hormones made by adrenal glands located on top of kidneys. Monamine neurotransmitter, and an organic compound that has catechol and a side chain amine

Question 19

Epinephrine

Answer 19

Adrenaline. Secreted by the medulla. Strong emotions

Question 20

Norepinephrine

Answer 20

Substance released predominantly from the ends of sympathetic nerve fibers and that acts to increase the force of skeletal muscle contraction of the heart. Vital to fight or flight.

Question 21

Sodium-potassium ATPase pumps

Answer 21

Helps maintain osmotic equilibrium and membrane potential in cells. Maintains the gradient of a higher concentration of sodium extracellularly and a higher level of potassium intracellularly

Question 22

Membrane potential

Answer 22

Potential gradient that forces ions to passively move in one direction: positive ions are attracted by the negative side of the membrane and negative ions by the positive one.

Question 23

Depolarization

Answer 23

When the membrane potential becomes less negative

Question 24

Hyperpolarization

Answer 24

When the membrane potential becomes more negative at a particular spot on the neurons membrane

Question 25

Capacitance

Answer 25

The electrical capacitance associated with a biological membrane

Question 26

Voltage dependent sodium channels

Answer 26

Responsible for the action potential initiation and propagation in excitable cells, including nerve, muscle, and neuroendocrine cell types

Question 27

Spikes

Answer 27

When a neuron’s membrane potential quickly rises in value and then drops

Question 28

Initial Segment

Answer 28

At the base of axons. It generates and shapes the action potential before it is propagated along the axon. Neuronal excitability depends crucially on this composition. It adapts to developmental and physiological conditions.

Question 29

Myelinated Axons

Answer 29

an axon surrounded by myelin and compromised of Schwann cells. It is electrically insulating, except for gaps in the sheath which are called the nodes of ranvier. The insulation increases the speed of transmission of action potentials.

Question 30

Nodes of Ranvier

Answer 30

Specialized regions in the axonal membrane that are not insulated by myelin. Gap in the myelin sheath of a nerve adjacent Schwann cells

Question 31

Saltatory Conduction

Answer 31

The way an electrical Im pulse skips from node to node down the fill length of an axon, speeding the arrival of the impulse at the nerve terminal comparison with the slower continuous progression of depolarization spreading down on unmyelinated axon

Question 32

Synaptic Vesicles

Answer 32

Small, electron-lucent vesicles that are clustered at presynaptic terminals. Store neurotransmitters and release them by calcium-triggered exocytosis. Made locally at terminals and regenerated after exocytosis

Question 33

Nerve muscle junction

Answer 33

Synaptic connection between the terminal end of a motor nerve and a muscle. Site for the transmission of action potential from nerve to muscle

Question 34

Glial Cells

Answer 34

Glial cells surround neurons and provide support for and insulation between them. They do not participate directly in synaptic interactions and electric signaling. They maintain the ionic milieu of nerve cells, modulating the rate of nerve cell propagation, and modulating synaptic action by controlling the uptake of neurotransmitters

Question 35

Astrocytes

Answer 35

specialized glial cells that outnumber neurons by over 5 five fold. They contiguously tile the entire CNS and exert many essential complex function in the healthy CNS

Question 36

Oligodendrocytes

Answer 36

a type of neuroglia found in the CNS of invertebrates and vertebrates that functions to produce myelin, and insulating sheath on the axons nerve fibers

Question 37

Schwann cells

Answer 37

The main glial cells of the PNS which wrap around axons of motor and sensory neurons to form the myelin sheath

Question 38

Microglia

Answer 38

Type of neuronal support cell occurring in the CNS of invertebrates and vertebrates that function primarily as an immune cell

Question 39

Satellite Glial Cells

Answer 39

Glial Cells that cover the surface of nerve cells bodies in sensory, sympathetic, and parasympathetic ganglia. Supply nutrients to the surrounding neurons and have some structural function

Question 40

Ependymal Cells

Answer 40

A specialized type of epithelial cell that lines the ventricular system of the brain and play a key role In the production of cerebrospinal fluid.