Nervous System Structure

Question 1

Glial cells

Answer 1

Aka neuralgia

Cells that support neuronal function
Capable of cellular division and healing in traumatic injury
Often responsible for brain cancer
Form myelin, maintain homeostasis, support and protect neurons in CNS and PNS

Question 2

Types of glial cells

Answer 2

Microglia
Ependymal cells
Satellite cells
Astrocytes
Oligodendrocytes
Schwann cells

Question 3

Microglia

Answer 3

CNS’s macrophages, arriving from white blood cells called monocytes

Phagocytose microbes and cellular debris

Question 4

Ependymal cells

Answer 4

Epithelial cells that line the space containing the cerebrospinal fluid
Connected through tight junctions and form the blood-cerebrospinal fluid barrier
Use cilia to circulate cerebrospinal fluid

Question 5

Satellite cells

Answer 5

Support the ganglia, which are groups of cell bodies in PNS

Serve support function, supply nutrients to surrounding cells, control micro environment. Similar role to Schwann cells of CNS

Question 6

Astrocytes

Answer 6

Star-shaped neuralgia in CNS that give physical support to neurons and help maintain the mineral and nutrient balance in interstitial space

Question 7

Oligodendrocytes

Answer 7

Have processes that wrap many times around axons in CNS to form myelin sheaths

Can extend its processes to wrap around up to 50 axons in CNS

Similar to Schwann cells in PNS

Question 8

Schwann cells

Answer 8

Wrap entire cell bodies around axons as myelin sheaths for conduction

Myelinating and non-myelinating Schwann cells
Non-myelinating involved in maintenance of axons and crucial for neuronal survival

Question 9

White matter

Answer 9

Areas of nervous system that are composed of myelinated axons of neurons

Question 10

Grey matter

Answer 10

Bundles of cell bodies of neurons

Question 11

Nodes of Ranvier

Answer 11

Gaps between myelinated areas on axons through which an action potential slightly slows as it passes

Question 12

Saltatory conduction

Answer 12

Action potentials jump from one node of Ranvier to the next, appearing to jump over myelinated areas, while in reality are just moving very fast through myelinated areas

Myelin insulates the axons and reduces capacitance of membrane, allowing faster conduction

Question 13

Three functions of neurons

Answer 13

1. Sensory (afferent): receive signals from receptor cell that interacts with environments and transfers signal to other neurons, brain filters 99% of sensory information, located more dorsally
2. Inter neurons: transfer signals from neuron to neuron, 90% of neurons in human body
3. Motor (efferent): carry signals to muscle or gland (called effector), located more ventrally

Question 14

Nerves

Answer 14

Bundles of neuron processes, this includes axons and dendrites

Known as tracts in CNS

Question 15

Reflex

Answer 15

Quick response to a stimulus that occurs without direction from CNS

Can require or not require interneuron

Negative feedback loop: stretch reflex senses stretching and motor neuron responds in opposite way to stretch change and flexes the muscle to return to normal length

Information sent to CNS and reflexes can be modulated by CNS

Question 16

Functions of CNS

Answer 16

Integrates nervous signals between sensory and motor neurons

Question 17

Functions of PNS

Answer 17

Handles sensory and motor functions of nervous system

Divided into somatic nervous system and autonomic nervous system

Question 18

Somatic nervous system

Answer 18

Part of PNS which serves to primarily respond to external stimuli
Sensory neuron cel bodies are located in dorsal root ganglion
Motor neurons inner gate skeletal muscle (voluntary movement) and cell bodies located in ventral horns of spinal cord, release acetylcholine to effectors

Question 19

Autonomic Nervous System (ANS)

Answer 19

Coordinates involuntary response to environment, altering processes within body to produce most adaptive physiological state and behavior

Sensory: receives signals primarily from viscera (organs in ventral body cavity)
Motor: conducts signals to smooth muscle, cardiac muscle, and glands
* sympathetic
* parasympathetic

Question 20

Sympathetic nervous system

Answer 20

“Fight or flight” responses

Increases heart rate and stroke volume
Constructs blood vessels around digestive and excretory organs

Signals originate in neurons whose cell bodies are in the spinal cord. Cell bodies of postganglionic neurons lie far from effectors (within paravertebral ganglion) for coordinated strong response

Question 21

Parasympathetic nervous system

Answer 21

“Rest and Digest”

Decreases heart rate and increases digestive and excretory activity

Signals originate in neurons whose cell bodies are found in the spinal cord and brain. Cell bodies of postganglionic neurons lie inside or near their effectors

Question 22

What neurotransmitters does the ANS use?

Answer 22

All preganglionic neurons in ANS use acetylcholine with nicotinic (cholinergic) receptors across the synapse

All postganglionic neurons in parasympathetic branch use acetylcholine and muscarinic receptors at the effectors (cholinergic)

Postganglionic neurons in sympathetic nervous system use norepinephrine or epinephrine (noradrenaline and adrenaline) with adrenergic receptors at the effectors

Question 23

Spinal cord

Answer 23

Acts as a bridge between peripheral nervous system and brain, conveying sensory and motor signals

Possesses limited integration functions such as walking reflexes, leg stiffening, and limb withdrawal from pain

Question 24

Lower brain

Answer 24

Earlier stage of evolutionary development

Brainstem, cerebellum, and diencephalon

Integrates unconscious activities such as respiratory system, arterial pressure, salivation, emotions, and reaction to pain and pleasure

Question 25

Brainstem

Answer 25

Controls basic involuntary functions necessary for survival

Consists of medulla, pons, and midbrain

Medulla: regulation of cardiovascular and respiratory systems, monitor CO2 in blood

Pons: coordinates communication between motor cortex and cerebellum, facilitating transfer of motor commands

Midbrain: relay station for auditory and visual signals

Question 26

Cerebellum

Answer 26

Involved in coordination and planning of movement

Receives and processes sensory, motor, and vestibular input

Question 27

Diencephalon

Answer 27

Consists of thalamus and hypothalamus

Thalamus: control center, or waystation because it processes almost all sensory info before reaching higher cortical centers. Receives motor commands from cortical areas on the way to spinal cord

Hypothalamus: maintains homeostasis in multiple systems such as temperature and water balance.

Hypothalamus and pituitary gland form major site of interaction between nervous and endocrine systems

Question 28

Higher brain

Answer 28

Consists of Cerebrum (cerebral cortex)

Most recently evolved portion incapable of functioning without lower brain

Controls consciousness, memory, cognition, planning, and emotion

Main endpoint for a majority of neuronal input

Influences our perception of the world and what we process

Question 29

Frontal lobe

Answer 29

Higher level executive functions such as planning and impulse inhibition

Includes motor cortex which controls voluntary movements
Map of specific sets of neurons to control certain body parts

Question 30

Parietal lobe

Answer 30

Contains somatosensory cortex

• maps the body’s sensation of touch
• sensitivity depending on area devoted to area of body

Question 31

Occipital Lobe

Answer 31

Where visual information is processed

Question 32

Temporal lobe

Answer 32

Processing of olfactory and auditory information

Question 33

Hippocampus and amygdala

Answer 33

Central to function of limbic system, which is primarily concerned with memory and emotion

Question 34

Corpus callosum

Answer 34

Connects two hemispheres of the brain

Question 35

Lateralization of cortical functions

Answer 35

Lateralized functions take place in one hemisphere or the other

Production and comprehension of language located in two areas in left brain

Question 36

Categories of the types of methods used for studying the brain

Answer 36

Lesion studies
Imaging
Electrical activity

Question 37

Sensory receptors

Answer 37

Used to bring information into the nervous system from the outside in the form of touch, sight, smell, and hearing

Transduct external or internal stimuli to electrical signals that can be conveyed to the CNS via sensory neurons

Each type has own neural pathway and termination point in CNS, resulting in various sensation

Question 38

Types of sensory receptors

Answer 38

Mechanoreceptors: touch
Thermoreceptors: temperature
Nociceptors: pain (more extreme stimuli)
Electromagnetic receptors: light
Chemoreceptors: taste, smell, blood chemistry

Question 39

Sensory information involved in somatosensory system

Answer 39

Sensations of touch, temperature and pain

Uses mechanoreceptors, thermoreceptors, and nociceptors

Question 40

Sensory adaptation

Answer 40

Stimulus that occurs repeatedly at same intensity level evokes fewer and fewer action potentials in sensory receptors

Nervous system filtering of less important information

Question 41

Phasic receptors

Answer 41

Sensory receptors that adapt very quickly and specialize in the perception of changes in stimuli

Question 42

Tonic receptors

Answer 42

Sensory receptors that react more slowly