Biology Chapter 4

Front 1

Cell Body/Soma

Back 1

The body in which the nucleus, also the location of the endoplasmic reticulum and ribosomes

Front 2

Dendrites

Back 2

Receive incoming messages from other cells

Front 3

Axon Hillock

Back 3

Integrates incoming signals, plays an important role in action potentials

Front 4

Action potential

Back 4

Transmission of electrical impulses down the axon

Front 5

Axon

Back 5

Long appendage that terminates in close to proximity to a target structure

Front 6

Myelin

Back 6

A tissue insulating neurons and prevents signal loss or crossing signals

Front 7

Myelin Sheath

Back 7

Maintains the electric signal within one neuron

Front 8

Nodes of Ranvier

Back 8

Areas in-between myelin sheath that are critical for rapid signal conduction

Front 9

Nerve Terminal/synaptic bouton

Back 9

An enlarged and flattened structure to maximize neurotransmission to the next neuron

Front 10

Synaptic Cleft

Back 10

Small space into which the terminal portion of the axon releases neurotransmitters

Front 11

Na/K ATPase

Back 11

A pump where 3 Na are taken out of the neuron and 2 K are taken in, with the use of ATP

Front 12

Depolarization

Back 12

Raising the membrane potential, Vm from its resting potential

Front 13

Hyperpolarization

Back 13

Lowering the membrane potential from its resting potential

Front 14

Threshold Value

Back 14

The electrical potential that must be reached in order to trigger an action potential

Front 15

Summation

Back 15

The additive effects of multiple signals

Front 16

Temporal Summation

Back 16

Multiple signals are integrated during a relatively short period of time

Front 17

Spatial Summation

Back 17

The additive effects are based on the number and location of the incoming signals

Front 18

Absolute Refactory period

Back 18

No amount of stimulation can cause another action potential to occur

Front 19

Relative refactory perid

Back 19

Must be a greater than normal stimulation to cause an action potential because the membrane is starting from a potential that is more negative than its resting value

Front 20

Saltatory Conduction

Back 20

The jumping of a signal from node of ranvier to node

Front 21

Presynaptic Neuron

Back 21

Neuron preceding the synaptic cleft

Front 22

Postsynaptic Neuron

Back 22

Neuron after the synaptic cleft

Front 23

Effector

Back 23

A post-synaptic cell that signals a gland or a muscle instead of another neuron

Front 24

Afferent Neurons

Back 24

Sensory neurons, transmit sensory information from receptors to the spinal cord and brain

Front 25

Efferent Neurons

Back 25

Motor neurons, transmit motor information from the brain and spinal cord to muscles and glands

Front 26

Interneurons

Back 26

Located predominantly in the brain and spinal cord and linked with reflexive behaviour

Front 27

CNS

Back 27

Composed of the brain and spinal cord

Front 28

White matter

Back 28

Axons and myelin sheaths

Front 29

Grey matter

Back 29

Unmyelinated cell bodies and dendrites

Front 30

Four Divisions of the Spinal Cord

Back 30

Cervical, thoracic, lumbar and sacral

Front 31

Vertebral Column

Back 31

Protects the spine and transmits nerves at the space between adjacent vertebrae

Front 32

DRG, Dorsal Root Ganglia

Back 32

Cell bodies of these sensory neurons found in this

Front 33

PNS

Back 33

Made up of nerve tissue and fibers outside the brain and spinal cord, includes all 31 pairs of spinal nerves and 10 of the 12 cranial nerves

Front 34

Somatic Nervous System

Back 34

Part of the PNS, consists of sensory and motor neurons distributed throughout the skin, joints and muscles

Front 35

Autonomic Nervous System

Back 35

Part of the PNS, regulates heartbeat, respiration, digestion and glandular secretions

Composed of two neurons called the preganglionic neuron and the postganglionic neuron

Front 36

Parasympathetic nervous system

Back 36

Part of the ANS, role is to conserve energy

Role to constrict pupil, stimulates flow of saliva, constricts bronchi, slows heartbeat, stimulates peristalis and secretion, stimulates bile release, contracts bladder

Front 37

Sympathetic Nervous system

Back 37

Activated by stress

Increases heart rate, blood flow to muscles increases, increases blood glucose concentration, relaxes the bronchi, decreases digestion and peristalsis, dilates the eyes to maximize light intake, releases epinephrine into the bloodstream

Front 38

Monosynaptic Reflex Arc

Back 38

There is a single synapse between the sensory neuron that receives the stimulus and the motor neuron that responds to it

Front 39

Postsynaptic Reflex Arc

Back 39

There is at least one interneuron between the sensory and motor neurons