Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histology > Nervous System Lecture > Flashcards

Nervous System Lecture Flashcards

1
Q

Describe the basic definition of the nervous system.

A

A network of nerve cells, supporting cells, nerve fibers, and receptors that enable the body to respond to changes in the internal and external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Identify the subdivisions and functional components of the nervous system (e.g. CNS = brain, spinal cord, nuclei; PNS = peripheral nerves, ganglia receptors).

A

Central Nervous System (CNS)
- Brain
- Spinal cord

	Peripheral Nervous System (PNS) -	Peripheral nerves  -	Ganglia  -	Receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the difference between ganglia and nuclei, including their locations

A

Nuclei –> collection of nerve cell bodies inside CNS
Ganglia –> collection of nerve cell bodies inside PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  1. Describe the basic structure of a neuron (e.g. cell body, neurolemma, nucleus, dendrites, axon, axon hillock, Nissl substance) including location and function.
A

Neurons –> Character cells of the nervous system. Form synapses with other neurons.
Components
- Cell body containing nucleus and cytoplasm (variable in size; cell membrane known as neurolemma)
- Several nerve fibers of varying length
- Cell processes (axons, dendrites)
- Rough endoplasmic reticulum (rER)
- Numerous mitochondria
- Axon hillock
- Nissl bodies (small clumps of rER seen with Toluidine Blue Stain and light microscope)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Neuroglia

A

= supporting cells for neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Astrocytes

A

–> largest neuroglial cells
o Function: provides nutrition and eliminates waste from neurons, covers nodes of -Ranvier, removes excess neurotransmitters from the synaptic cleft, works with pia mater in the formation of blood-brain barrier, regulates extracellular K+ concentration, forms a fine meshwork (neuropil) in areas devoid of neurons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oligodendrocytes

A

–> smaller in size than astrocytes with fewer, less branching processes, usually aligned in columns between axons,
o Function: forms myeline sheath around CNS axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Microglia (cells of Hortega)

A

–> smallest neuroglial cells, small, darkly-staining, elongated nucleus with a thin layer of cytoplasm, few, highly branches cell processes
o Function: mobile, phagocytic cells. Thought to be important in removing invading organisms and neoplastic cells; removes injured cells and cell debris; moderate immune reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ependymal cells

A

–> forms single layer of cuboidal to columnar-shaped cells lining the brain ventricles and central canal of spinal cord. Lacks an external lamina; extensive basal infoldings; luminal surface has cilia and microvilli
o Function: modified at areas within ventricles to work with capillary loops (*choroid plexus) in the transport of fluid and secreted materials to form the cerebrospinal fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Schwann cells

A

–> develop from neural crest ectoderm
o Function: support myelinated and unmyelinated neurons, removes cell debris; guides regrowth of PNS axon, insulates axons, increases speed of conduction of nerve impulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Satellite cells

A

–> single layer of small cuboidal cells covering the surface of ganglia
o Function: Insulate ganglia, provide route for metabolic exchanges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Identify the composition, function, and location of the blood brain barrier and its implications in health and disease.

A

A network of blood vessels and tissue that is made up of closely spaced cells and helps keep harmful substances from reaching the brain
- Capillary endothelium that has tight junctions that restrict movement of water and other molecules through the intercellular space.
- External lamina covered with food processes of astrocytes

Functions:
* Selective permeability to substances
* Free passage of O2, CO2, certain lipid-soluble molecules
* Movement of K+ and dopamine restricted
Location –> absent in midline structures of the brain bordering the 3rd and 4th ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Myelinated nerve fibers

A

axons are surrounded by concentric layers of Schwann cell or Oligodendrocyte plasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Myelinated cells in CNS and PNS

A
  • CNS –> found within the CNS and optic nerve
  • PNS –> most peripheral cranial and spinal nerves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Schwann cells

A

surround a relatively short axon segment, thickness of myeline sheath controlled by Schwann cells, myelin sheaths lined up in series along axon, nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Identify the location of myelinated and unmyelinated nerves in both the CNS and PNS, including examples of each.

A

Myelinated
PNS –> Schwann cells
Peripheral nerve
CNS –> Oligodendrocytes
Spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the mechanism of nerve impulse conduction in both myelinated and unmyelinated nerve fibers.

A

Unmyelinated
1. Appropriate stimulus increases cell membrane permeability at site of stimulation
2. Organization of cell membrane polarity is reversed generating an action potential
3. Wave depolarization followed by wave of repolarization moved unidirectionally over the neuron

Myelinated
1. Appropriate stimulus causes membrane depolarization of neuron, followed by repolarization
2. Depolarization moves down axon hillock to area of myelinated segment of axon
3. Electrical impulse moves over surface of myelin sheath to first node of Ranvier
4. Depolarization of axolemma occurs at first node of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Conduction velocity

A
  • Directly correlated to diameter of axon
  • Velocity increased through myelination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A fibers

A

myelinated axons of large sensory nerves (touch, pressure, proprioception, heat, and cold) and all nerve fibers supplying skeletal muscle (conduction velocities up to 130 m/second)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

B fibers

A

smaller diameter myelinated sensory fibers from skin and viscera, and preganglionic autonomic fibers (conduction velocities up to 10 m/second).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

C fibers

A

smallest diameter fibers; unmyelinated sensory fibers carrying pain, temperature, touch and pressure from skin and viscera; postganglionic autonomic fibers (e.g. pupil diameter, heart rate, peristalsis, urination)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Synapse

A

electrochemical transmission sites between neurons or neurons and effector cells
- Formed at junctions with other neurons or muscle fells (neuromuscular junctions or motor end plates)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Components of synapse

A
  • Components:
    o Presynaptic membrane –> portion of the axolemma covering bulb-shaped terminal end of axon processes
    o Synaptic cleft –> 6-30 nm wide gap between presynaptic and post synaptic membranes
    o Post synaptic membrane –> axolemma of the neuron immediately across from the presynaptic membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Identify what neurotransmitters are, where they are generally located, and what they do; also give at least two examples.

A

Chemical substances stored within or bound to small membranous sacs (synaptic vesicles)
- Synaptic vesicles congregated within cytoplasm of terminal boutons; contain 10,000-100,000 neurotransmitter molecules
- Usually stimulate or inhibit a particular activity
o Common neurotransmitters –> acetylcholine (Ach), epinephrine/norepinephrine, serotonin, dopamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe the basic definition of receptor.

A

A molecular structure that reacts with a single neurotransmitter
- Can be an enzyme and/or membrane structural protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cholinergic

A
  • Ach used as a neurotransmitter
  • Muscarinic
    o Involved G-protein signaling cascade
    o Predominantly involved with modulating neuron activity and decreasing cardiac activity
  • Nicotinic
    o Subclass of cholinergic receptors
    o Involves opening membrane Na+ receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Adrenergic

A
  • Epinephrine and norepinephrine used as neurotransmitters
  • Alpha (a)
    o Stimulated vasoconstriction, dilation of pupils, relaxation or intestinal smooth muscle, contraction of internal urinary and anal sphincter smooth muscle
  • Beta (B)
    o Cardio acceleration, increased strength of heart contractions, lipolysis. Vasodilation, relaxation of intestinal smooth muscle, relaxation of uterine smooth muscle, relaxation of urinary bladder smooth muscle
28
Q

Meninges

A

connective tissue covering CNS

29
Q

Pia mater

A

connective tissue layer adherent to the CNS, and dorsal and ventral roots. Vasculature layer of meninges (connects blood vessels)

30
Q

Arachnoid mater

A

Adhered to overlying mater, except for strands of arachnoid mater that connect to the pia mater (arachnoid trabeculae). Subarachnoid space filled with CSF communicates with the 4th ventricle via pared Foramina of Luschka; enlarged in some locations to form cisterns.

31
Q

Dura mater

A

“tough mother.” Tightly adhered to periosteum of skill; can be separated by trauma, forming an epidural space (collects blood). Separated into periosteal and meningeal layers at certain locations to form valveless channels that conduct venous space (collects blood).

32
Q

Cross section morphology of spinal cord

A
  • White matter
  • Grey matter
33
Q

White matter

A

superficial location; contains myelinated and unmyelinated axons, astrocytes, oligodendrocytes, and blood vessels.

34
Q

Grey matter

A

located within the spinal cord in the shape of a modified “H”; consists of: neuron cell bodies and processes = majority are unmyelinated; astrocytes; oligodendrocytes; microglial cells; capillaries organized into shape

35
Q

Function of spinal cord

A

receives sensory information from muscles, tendons, joints, ligaments, skin, and viscera. Sends motor commands to muscles and glands. Reflex center; provides subconscious responses of muscles and glands to specific stimuli, conducts information to and from the brain involved with posture, movement, and visceral aspect of behavior.

36
Q

Afferent systems

A

(carry sensory information to the spinal cord)
o GSA = pain, temperature, touch, general proprioception
 Free nerve endings – pain, temperature, touch
 Pacinian corpuscles – pressure, crude touch, vibration, and tension
 Meissner’s corpuscle

37
Q

Efferent systems

A

(carry motor information from the spinal cord)
o GSE = contraction of skeletal muscle
o GVE = contraction of smooth muscle in the walls of blood vessels supplying skeletal muscle and glands of the skin

38
Q

Receptor definition

A

A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific effect in the cell.

39
Q

Free nerve endings

A
  • Numerous small terminal branches of sensory (afferent) nerve fibers
  • Detection of pain, temperature, touch
  • Located in supporting tissues throughout the body
  • Small diameter fibers with a slow rate of conduction
40
Q

Pacinian corpuscles

A
  • Large, encapsulated receptors (1-4 mm in length); have the appearance of the “onion”
  • Detect pressure, crude touch, vibration, and tension
  • Located in deeper layers of the skin, ligaments, joint capsules, some serous membranes, mesenteries, some viscera, some erogenous areas
41
Q

Meissner’s corpuscles

A
  • Small, encapsulated receptors
  • Located in dermal papillae of skin (*especially fingertips, soles of feet, eyelids, lips, nipples, genitalia)
42
Q

Reflex

A

an involuntary, short term, stereotypical response serving the immediate needs of an organism

43
Q

Reflex arc

A

any activity to a stimulus requiring an afferent-to-efferent pathway linkage

44
Q

Myotatic reflex arc

A

simplest reflex arc; single pseudounipolar neuron; central sensory axon synapses on dendrites of alpha motor neurons in the ventral horn gray

45
Q

Steps of reflex arc

A
  1. Tapping the patellar tendon stretches muscle fibers of the quadriceps femoris muscle
  2. Stretching of muscle fibers causes a simultaneous stretching of the outer covering of muscle spindles associated with the skeletal muscles
  3. Impulses are sent from the muscle spindle through the spinal nerve associated with the quadriceps muscle to the dorsal root ganglion associated with this muscle spindle
  4. The impulses travel in the dorsal roots and pass through the dorsal horn and intermediate gray matter
  5. The impulse is carried to the ventral horn gray matter where it synapses on motor neuron
  6. Impulses from the motor neuron exit the ventral gray matter by traveling in the ventral roots
  7. Impulses travel from ventral roots to join the spinal nerve which supplies motor input to the quadriceps
  8. The quadriceps muscle is stimulated to contract suddenly, producing rapid extension of the stifle joint
46
Q

Composition of cerebrum

A

a convoluted cortex of gray matter covering a central mass of white matter called the medulla

47
Q

Functional organization of cerebrum

A

Functional organization
- Frontal lobe = motor functions; higher functions (reasoning, etc)
- Parietal lobe = pain, temperature, touch, taste
- Temporal lobe = hearing
- Occipital lobe = vision
- Olfactory lobe = smell

48
Q

Outer cerebral cortex of cerebrum (gray matter)

A
  • Neurons, neuron cell processes, central nervous system
49
Q

Inner medulla of cerebrum (white matter)

A
  • Axons, central nervous system glial cells, blood vessels
50
Q

Stratification of cerebrum –>

A

Molecular layer
Outer granular layer
Outer pyramidal cell layer
Inner granular cell layer
Inner pyramidal cell layer
Fusiform cell layer

51
Q

Gross structure cerebellum

A
  • Dorsal division of the metencephalon
  • Two lateral cerebral hemispheres separated by a midline mass (vermis)
  • Surface covered with narrow ridges (folia) separated by grooves (sulci)
52
Q

Cerebellum function

A
  • Receives information regarding head movements; muscle, tendon, joint, and ligaments stretch from ipsilateral (*same side of the body). Modulates pools of motor neurons in the ipsilateral spinal cord to coordinate posture and movement
53
Q

Microanatomy of cerebellum

A
  • Gray matter of cerebral cortex covers underlying white matter
    o Molecular layer (outer layer)
    o Purkinje cell layer (middle layer)
    o Granular cell layer (inner layer)
  • White matter –> branches out into the cortex like branches of tree (arbor vitae)
    o Cerebral peduncles (stalks of white matter connecting the cerebellum to the brain stem)
    o Afferent fibers from rostral, middle, and caudal cerebellar peduncles
    o Axons from Purkinje cells
54
Q

Ventricle system

A

a number of interconnecting cavities which are remnants of the lumen of the embryonic neural tube. The chambers include two lateral ventricles connected to the third ventricle by the interventricular foramina (interventricular foramen of Monroe), and a fourth ventricle connected to a third ventricle by the mesencephalic aqueduct (aqueduct of Silvius)

55
Q

Characteristics CSF

A
  • A fluid containing of a filtrate of blood, combines with secretions of cells lining the interior of the four ventricles of the brain
  • Fills the interior of the ventricle system and central canal of spinal cord
  • Differs significantly from tissue fluid = less calcium, potassium, glucose, and protein; more magnesium, sodium and chloride.
56
Q

Production and circulation of CSF

A
  • Formed at specialized structures within each ventricle called choroid plexus. Choroid plexus = an extensive in-folding of ependymal/pial cells combined with a tuft of arterioles suspended between the pial layer of the developing ventricle
  • Majority of CSF produced in lateral ventricles
  • CSF circulation patters: lateral ventricles –> interventricular foramen –> 3rd ventricle –> mesencephalic aqueduct –> 4th ventricle –> rt. & lateral apertures –> subarachnoid space
57
Q

Absorption CSF

A
  • Rapid turnover of CSF
  • Absorption of CSF occurs at arachnoid villi and is controlled by CSF/blood pressure gradients
  • Arachnoid villi = evaginations of arachnoid layer into dural sinuses of the brain. Acts as pressure-dependent, unidirectional valves
58
Q

Autonomic nervous system

A
  • Not under voluntary control
  • Divided into sympathetic and parasympathetic nervous systems
59
Q

Preganglionic neuron

A

located within CNS

60
Q
  • Preganglionic axons
A

nerve fibers extending from preganglionic of PNS

61
Q
  • Postganglionic neuron
A

located in an autonomic ganglion of PNS

62
Q
  • Postganglionic axons
A

nerve fibers extending from postganglionic neuron; synapse on effector organ

63
Q

Sympathetic Nervous System

A
  • “Fight or Flight” responses
  • Dilates pupils
  • Relaxation of ciliary m.
  • Increases HR
  • Increases blood flow to skeletal muscle
  • Decreased blood to skin
  • Increases blood pressure
  • Increases respiration
  • Decreases peristalsis
  • Relaxation of the muscle in bladder wall
  • Sympathetic impulses from preganglionic sympathetic neurons located in the intermediolateral cell column of thoracolumbar spinal cord
  • Preganglionic sympathetic axons synapse on postganglionic sympathetic neurons in sympathetic ganglia
  • Postganglionic sympathetic axons synapse on structures od effector organs
64
Q

Parasympathetic Nervous System

A
  • Decreases HR
  • Constricts pupil
  • Constricts ciliary muscle
  • Increases peristalsis
  • Urination
  • Defecation
  • Constriction of bronchi
  • Impulses originate from preganglionic parasympathetic neurons in nuclei located in the brainstem or sacral spinal cord
  • Preganglionic parasympathetic axons exit midbrain and hindbrain with cranial nerves III, VII, IX & X; synapse on postganglionic parasympathetic axons of parasympathetic ganglia, usually located within the effector organ
  • Postganglionic parasympathetic axons synapse on structures of effector organs
65
Q

Sympathetic vs Parasympathetic

A
  • Parasympathetic effects are more specific, discrete & local; sympathetic effects are more widespread
  • Postganglionic sympathetic axons are adrenergic (release noradrenaline); post ganglionic parasympathetic axons are cholinergic (release acetylcholine); *both preganglionic parasympathetic & sympathetic axons are cholinergic (release ACH)

Histology (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions