Biology Chapter 44

Front 1

Sensory Receptors

Back 1

detects the stimulus

Front 2

Motor Effectors

Back 2

respond to the stimulus

Front 3

Sensory Neurons

Back 3

carry impulses from sensory receptors to the central nervous system

Front 4

Central Nervous System (CNS)

Back 4

the brain and spinal cord

Front 5

Motor Neurons

Back 5

carry impulses from the CNS to the effectors - muscles and glands

Front 6

Interneurons

Back 6

located in the brain and spinal cord, help provide more complex reflexes and higher associative functions, including learning and memory

Front 7

Peripheral Nervous System (PNS)

Back 7

sensory and motor neurons

Front 8

Somatic Nervous System

Back 8

motor neurons that stimulate skeletal muscles to contract

Front 9

Autonomic Nervous System

Back 9

regulate the activity of the smooth muscles, cardiac muscle, and glands

Front 10

Cell Body

Back 10

the enlarged region containing the nucleus

Front 11

Dendrites

Back 11

cytoplasmic extensions from the cell body

Front 12

Axons

Back 12

takes impulses away from the cell body

Front 13

Neuroglia

Back 13

the supporting cells, both structurally and functionally, or neurons

Front 14

Schwann Cells

Back 14

produces myelin in the PNS

Front 15

Oligodendrocytes

Back 15

produce myelin in the CNS

Front 16

Myelin Sheath

Back 16

a insulating covering consisting of multiple layers of compacted membrane

Front 17

White Matter

Back 17

myelinated axons in the CNS

Front 18

Gray Matter

Back 18

unmyelinated dendrites and cell bodies in the CNS

Front 19

Nerves

Back 19

myelinated axons bundled together in the PNS

Front 20

Nodes of Ranvier

Back 20

small gaps that interrupt the myelin sheath at intervals of 1 to 2 micrometers

Front 21

Resting Potential

Back 21

when a neuron is not stimulated it maintains a very small charge

Front 22

Sodium-Potassium Pump

Back 22

brings two potassium ions into the cell for every three sodium ions it pumps out

Front 23

Ion Leakage Channels

Back 23

membrane proteins that form pores through the membrane, allowing the flow of specific ions (like K or Na) in and out of the cell

Front 24

Equilibrium Potential

Back 24

balance between the diffusional force and the electrical force

Front 25

Nernst equation

Back 25

quantitative expression for the equilibrium potential

Front 26

Grade Potential

Back 26

small transient changes in membrane potential, caused by the activation of a class of channel proteins

Front 27

Gated Ion Channels

Back 27

channel proteins that allow for graded potentials, can open and close, selective in that it only allows diffusion of one type of ion

Front 28

Ligands

Back 28

chemical groups that attach to larger molecules to regulate or contribute to their function

Front 29

Depolarization

Back 29

the membrane potential is more positive

Front 30

Hyperpolarization

Back 30

the membrane potential is more negative

Front 31

Summation

Back 31

the ability of graded potentials to combine

Front 32

Action Potential

Back 32

when depolarization is reached, a nerve impulse, is produced in the region where the axon arises from the cell body

Front 33

Threshold Potential

Back 33

the level of depolarization needed to produce an action potential

Front 34

Voltage-Gated Ion Channels

Back 34

channels that open and close in response to changes in membrane potential; the flow of ions controlled by these channels creates the action potential, found in neurons and muscle cells

Front 35

Saltatory Conduction

Back 35

the impulses jump from node to node in myelinated axons

Front 36

Synapses

Back 36

intercellular junctions, the branches of the axons form junctions with other dendrites of neurons, muscles cells, or other glands

Front 37

Electrical synapses

Back 37

direct cytoplasmic connections formed by gap junctions between the pre and postsynaptic neurons

Front 38

Chemical Synapses

Back 38

presynaptic and postynaptic cells appear to touch but when viewed under another microscope their is a separating factor

Front 39

Synaptic Cleft

Back 39

a narrow space that separates the two cells in a chemical synapse

Front 40

Synaptic Vesicles

Back 40

end of the presynaptic axon is swollen and contains numerous amounts of these

Front 41

Neurotransmitters

Back 41

the chemicals that are packed within the synaptic vesicles

Front 42

Receptor Proteins

Back 42

neurotransmitters diffuse to the other side of the cleft and bind to the chemical or ligand- gated proteins which are in the membrane of the post-synaptic cell

Front 43

Acetycholine (ACh)

Back 43

neurotransmitter that crosses the synapse between a motor neuron and a muscle fiber

Front 44

Neuromuscular Junction

Back 44

the synapse between a motor neuron and a muscle fiber

Front 45

Excitatory Postsynaptic Potential (EPSP)

Back 45

the site on the postsynaptic membrane that produces a depolarization, this can open the voltage-gated channels for Na and K that are responsible for action potentials

Front 46

Acetylcholinesterase (AChE)

Back 46

an enzyme in the postsynaptic membrane, that eliminates ACh, this allows the muscle to relax

Front 47

Glutamate

Back 47

the major excitatory neurotransmitter in the vertebrate CNS, stimulate action potentials

Front 48

Inhibitory Postsynaptic Potential (IPSP)

Back 48

hyperpolarization, it makes the membrane even more negative than it is at rest

Front 49

Glycine, GABA

Back 49

inhibitory neurotransmitters, allow the opening of the Cl- ligand-gated channel

Front 50

Epinephrine

Back 50

causes fight or flight response, fast and strong heartbeat etc

Front 51

Dopamine

Back 51

controls body movements and other functions

Front 52

Serotonin

Back 52

regulations of sleep, and has implications in emotional states

Front 53

Substance P

Back 53

an important neuropeptide released at synapses in the CNS by sensory neurons activated by painful stimuli

Front 54

Enkephalins

Back 54

released by axons descending from the brain into the spinal cord , inhibit the passage of pain information back up to the brain

Front 55

Endorphins

Back 55

released by neurons in the brain stem, also block the perception of pain

Front 56

Nitric Oxide

Back 56

regulatory molecule in the body, innervates the gastrointestinal tract, penis, respiratory passages, and cerebral blood vessels, released from the amino acid arginine, smooth muscle relaxation

Front 57

Synaptic Integration

Back 57

the process of IPSP subtracting the depolarizing effect of the EPSP, deterring the membrane potential from reaching the threshold

Front 58

Spatial Summation

Back 58

many different dendrites produce EPSP that sum to the threshold voltage

Front 59

Temporal Summation

Back 59

one dendrite producing repeated EPSP that sum to the threshold voltage

Front 60

Habituation

Back 60

cells in the nervous system are exposed to a constant stimulus that produces a chemically mediated signal for a prolonged period, the cells may lose their ability to respond to the stimulus

Front 61

Hindbrain

Back 61

cerebellum, pons, and medulla oblongata, the extension of the spinal cord devoted primarily to coordinating motor reflexes

Front 62

Optic Tectum

Back 62

receives and processes visual information

Front 63

Forebrain

Back 63

contains the diencephalon and the telencephalon

Front 64

Diencephalon

Back 64

thalamus and hypothalamus

Front 65

Thalamus

Back 65

an integration and relay center between incoming sensory information and the cerebrum

Front 66

Hypothalamus

Back 66

participates in basic drives and emotions and controls the secretions of the pituitary gland

Front 67

Telencephalon

Back 67

"end brain", front of the forebrain, devoted to associative activity, includes the cerebrum

Front 68

Cerebrum

Back 68

the center for correlation, association, and learning in the mammalian brain, it receives sensory data from the thalamus and issues motor commands to the spinal cord via descending tracts of axons

Front 69

Cerebral Hemispheres

Back 69

split the cerebrum into left and right sections

Front 70

Corpus Callosum

Back 70

connects the two sections of the brain

Front 71

Cerebral Cortex

Back 71

densely packed with nerve cells on the outside of the cerebrum and accounts for most neural activity of the cerebrum

Front 72

Primary Motor Cortex

Back 72

along the gyrus (convolution) on the posterior border of the frontal lobe, each part is associated with movement of a different part of the body

Front 73

Primary Somatosensory Cortex

Back 73

this area receives input from sensory neurons serving skin and muscle senses in a particular part of the body

Front 74

Association Cortex

Back 74

the portion of the cerebral cortex that is not occupied by these motor and sensory cortices

Front 75

Basal Ganglia

Back 75

aggregates of neuron cell bodies, which receive sensory information from ascending nerve tracts and motor commands from the cerebral cortex and cerebellum

Front 76

Limbic System

Back 76

an evolutionarily ancient group of linked structures deep within the cerebrum that are responsible for emotional responses

Front 77

Reticular-Activating System

Back 77

controls consciousness and alertness

Front 78

Wernickes Area

Back 78

language comprehension and the formulation of thoughts into speech

Front 79

Brocas Area

Back 79

responsible for the generation of motor output needed for language communication

Front 80

Long - Term Potentiation (LTP)

Back 80

synapses that are used intensively for a short time display more effective synaptic transmission on subsequent use

Front 81

Alzheimer Disease

Back 81

a condition in which the memory and thought processes of the brain become dysfunctional

Front 82

Reflexes

Back 82

the sudden, involuntary movement of muscles, is produced in the spinal cord, a rapid motor response to a stimulus

Front 83

Ganglia

Back 83

aggregations of neuron cell bodies located outside the CNS

Front 84

Dorsal Root

Back 84

axons of sensory neurons enter the dorsal surface of the spinal cord

Front 85

Ventral Root

Back 85

motor axons leave from the ventral surface of the spinal cord

Front 86

Dorsal Root Ganglia

Back 86

cell bodies of sensory neurons are grouped together outside each level of the spinal cord

Front 87

Sympathetic Division

Back 87

the preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord, activates body for fight-or-flight response

Front 88

Parasympathetic Division

Back 88

preganglionic neurons originate in the brain and sacral regions of the spinal cord, antagonizes the actions of the sympathetic, promotes relaxation and digestion