FINAL EXAM Flashcards
(138 cards)
1
Q
Define Nissl body
A
well developed rough ER, involved in metabolic activity
2
Q
Do primary brain tumors originate from NEURONS in the brain or the SUPPORTING CELLS?
A
Supporting cells (neuroglial cells). 1. neurons are amitotic and cannot divide 2. supporting cells are able to divide, and proliferate, causing tumor
3
Q
Why are neurons amitotic?
A
they do not contain centrioles, which are needed for cells to divide
4
Q
Describe the structural organization of a tract or nerve
A
(innermost –> outermost)
neuron –> endoneurium –> fascicle –> perineurium –> epineurium –> tract/nerve
5
Q
define Endoneurium
A
connective tissue that covers each axon
6
Q
Define tract
A
bundle of axons in the CNS
7
Q
Name and describe the function of supporting cells IN THE CNS (4)
A
- astrocytes: involved in forming the blood-brain barrier
- microglia: clean cell debris
- ependymal cells: beat cilia to move cerebrospinal fluid (CSF)
- oligodendrocytes: myelinates axons
8
Q
Name and describe the function of supporting cells IN THE PNS (2)
A
- Schwann cells: myelinate axons, contain neurilemma
- Satellite cells: act as chemical barrier
9
Q
Which part of a neuron is known as the secretory region and why?
A
Axon terminals because they release neurotransmitters into extracellular space
10
Q
define epineurium
A
connective tissue that covers the bundle of perineurium-covered fascicles
11
Q
define nerve
A
bundle of axons in the PNS
12
Q
Define ganglion
A
cluster of neuron cell bodies in the Peripheral Nervous System (PNS)
13
Q
define perineurium
A
connective tissue that covers fascicle
14
Q
Define nucleus
A
cluster of neuron cell bodies in the Central Nervous System (CNS)
15
Q
Which part of a neuron is known as the conducting region and why?
A
Axon because it generates and transmits action potentials away from the cell body
16
Q
Which part of a neuron is known as the receptive center and why?
A
Dendrites because they receive and convey electrical signals towards the cell body
17
Q
How many axons can each neuron have?
A
Each neuron can only have one axon
18
Q
Which part of a neuron is known as the biosynthetic center and why?
A
Cell body because all biosynthetic activities occur in the cell body
19
Q
define Nodes of Ranvier
A
spaces between adjacent myelin shealths
20
Q
define neurilemma
A
outermost nucleated cytoplasmic layer of schwann cells that surrounds the axon of the neuron
21
Q
which type of supporting cells are involved in the formation of the Blood-Brain Barrier?
A
Astrocytes
22
Q
What is the function of the Blood Brain Barrier
A
- prevents brain and nerve cells from contact with blood
- additional shock absorption and insulation
- provides nutrients and oxygen to the brain
23
Q
explain why myelinated axons in the CNS do not regenerate when severed
A
they have no regeneration tube because neurilemma is not present. they are amitotic so they cannot replicate
24
Q
explain why axsons in the PNS can regenerate when severed
A
axons in the PNS have regeneration tube formed by the neurilemma from the schwann cell and nuclei to replicate
25
why are impuses conducted **faster in a larger** **myelinated axon** and **slower in a smaller unmyelinated axon**?
1. **diameter of axon:** larger axons transmit impulses faster because there is *less resistance*
2. **degree of myelination:** myelinated axons transmit impulses faster because *myelinated axons use saltatory conduction* (faster) and *unmyelinated axons use continous conduction* (slower)
26
Describe the **resting membrane potential**
resting state with no movement, more Na+ ions outside, more K+ ions inside
27
describe the **depolarization phase** of an **action potential**
Na+ influx (enters the cell)
28
describe the **repolarization phase** of an **action potential**
K+ efflux (exits the cell), occurs after action potential is reached
29
describe the **hyperpolarization phase** of an **action potential**
more K+ efflux (exiting the cell) then return to Resting membrane potential
30
what is the **absolute refractory period** and the **relative refractory period** of an action potential?
* **absolute refractory period:** occurs when the sodium gates are still open (**depolarization phase**) and the **neuron is unable to initiate a new action potential**
* **relative refractory period:** occurs when the sodium gates are closed (**repolarization phase**) and a **strong stimulus causes initiation of a new action potential**
31
how does the body differ between a strong stimulus and a weak stimulous?
more frequent action potentials indicate a strong stimulus
less frequent action potentials indicate a weak stimulus
32
Name and describe the **structural classes** of neurons (3)
1. **Uni/psuedo polar:** a single process extending from the cell body, divided into peripheral and central processes
2. **bipolar:** two processes attached to the cell body (one dendrite, one axon); found only in eye, ear, and olfactory mucosa
3. **multipolar:** many processes attached to the cell body (many dendrites, one axon)
33
which **structural class** of neurons is most abundant in the body?
multipolar
34
name and describe the **functional classes** of neurons (3)
1. **sensory (afferent) neurons:** carry impulses _toward_ the CNS
2. **motor (efferent) neurons:** carry impulses _away from_ the CNS
3. **association neurons (interneurons):** conduct impulses within the CNS
35
which **functional class** of neurons is most abundant in the body?
association neurons (interneurons) make up 90% of the nerves in the body
36
name and describe the types of nerve fibers (3)
1. **group A:** largest diameter, heavily myelinated; transmits impulses at **150 m/s**
2. **group B:** intermediate diameter, lightly myelinated; transmits impulses at **15 m/s**
3. **group C:** smallest diameter, unmyelinated; transmits impulses at **1 m/s**
37
which type of **nerve fiber** has the **fastest conduction**? why?
Group A fibers because they have the *largest diameter*, which allows for the lowest resistance during conduction
38
which type of **nerve fiber** has the **slowest conduction velocity**? why?
Group C fibers, because they have the *smallest diameter* and thus the highest resistance during conduction
39
What happens to the conduction velocity when myelinated axons become demyelinated?
**conduction velocity decreases** because myelin insulate the axonal membrane which reduces the ability of current to leak out of the axon, thus increasing the distance along the axon that a current can flow
40
Name the structures protecting the brain (4)
Cranium, Meninges, Cerebral Spinal Fluid, Blood Brain Barrier
41
Name the types of meninges (3)
Outermost --\> Innermost
1. Dura Mater: _double-layered_, tough and inflexible
2. Arachnoid mater
3. Pia mater
42
List where **Cerebral Spinal Fluid** is located both inside and outside the brain
* Inside: two lateral ventricles (**cerebral cortex**), third (**diencephalon**) and fourth (**pons + medulla oblongata**) ventricle
* outside: subrarachnoid space
43
Where is the location of the **interventricular foramen**?
connects the paired **(2)** **lateral ventricles** with the **third ventricle** at the **midline** of the brain
44
give the location of the **cerebral aqueduct**
connects the **third ventricle** in to the **fourth ventricle** within the **midbrain**
45
What supporting cell lines the ventricles of the brain and what is its function?
**ependymal cells**, function is to circulate cerebrospinal fluid
46
What are the four regions of the brain
Cerebrum, Cerebellum, Diencephalon, Brainstem
47
Define **gryus**
the **ridge (raised area)** of wrinkled gray matter in the brain
48
define **sulcus**
the **grooves** between two gyri
49
define **fissure**
the deeper sulcus
50
define **corpus callosum**
the **pathway for communication** between the two hemispheres of the cerebral cortex, located deep within the cerebrum
51
define **gray matter**
The region of the brain with many cell bodies and dendrites
52
Define **white matter**
the region of the brain with many axons
53
define **commissural tract**
enables the two sides of the cerebrum to communicate with each other
54
define **projection tract**
transmit impulses from the cerebrum to parts of the lower brain and spinal cord
55
define **association tract**
connect areas of the cerebral cortex within the SAME hemisphere
56
what type of tract is the **corpus callosum**
commisural
57
what type of tract is the **arcuate fasciculus**?
association
58
what type of tract is the **pyramidal tract**?
projection
59
name the 5 lobes in the cerebral hemisphere
Frontal, parietal, occipital, temporal, insula
60
which lobe in the cerebral hemisphere cannot be viewed on the external surface?
Insula
61
Name the sulci that separate the cerebral lobes (3)
* **Central sulcus:** separates *frontal* and *parietal*
* **Lateral sulcus:** separates *frontal + parietal* from *temporal*
* **Parieto-occipital sulcus:** separates *parietal* and *occipital*
62
name the functional areas of the cerebral cortex (3)
Motor, sensory, association
63
Name and describe the function of the four **motor** areas of the **frontal lobe**
* **primary:** voluntary movement of skeletal muscles
* **premotor:** repitition and memory
* **frontal eye:** eye muscle movement
* **Broca's Area:** speech
64
what is the significance of the **precentral gyrus**
* structure on the surface of the frontal lobe called the *primary motor area*
* controls the voluntary movements of skeletal muscles
65
discuss the **contralateral control** of voluntary skeletal muscle movements by the cerebral cortex
the right side of the body is connected to the left side of the brain and the left side of the body to the right side of the brain
66
what would be the consequence of damage to the **precentral gyrus** in the **left cerebral hemisphere?**
degeneration of **left pyramidal tract**, loss of voluntary skeletal muscle movements on **right side** (right side paralysis)
67
What would be the consequence of damage to the **postcentral gyrus** in the **right cerebral hemisphere?**
loss of sensation in the **left** side of the body
68
what would be the consequence of damage to the Broca's area
inability to speak
69
What is Broca's aphasia
inability to speak or communicate verbally
70
What is Wernicke's aphasia?
"word salad"; random, nonensical, or incoherent sound or speech
71
Why can **right side paralysis** be sometimes accompanied by Broca's aphasia?
Broca's area is **only on the left frontal lobe.** right side paralysis occurs from left side cerebral brain damage
72
what would be the consequence of damage to the **right postcentral gyrus?**
Somatosensory damage (homunculus); left side loss of sensation
73
Name and describe the function of the (3) main **cerebral basal nuclei**
1. **caudate nucleus:** motor and behavioral functions
2. **putamen:** motor function and physical movement, skeletal muscle innervation
3. **globus pallidus:** voluntary movement regulation
74
What is the pathogenesis of Parkinson's disease?
damage to the domapinergic neurons
75
Why is L-DOPA is used to manage Parkinsons disease and not dopamine?
L-DOPA is nonpolar and a precursor to dopamine. L-DOPA can cross the BBB to reach the basal nuclei and convert into dopamine. Dopamine is polar and cannot cross the BBB
76
Which area in the diencephalon is referred to as the "gateway to the cerebral cortex"? Why?
**thalamus** because all sensory input must stop in the thalamus before projecting to their respective cerebral cortex
77
name two areas in the diencephalon with endocrine function
Epithalamus and Hypothalamus
78
**structurally**, how is the brain stem similar to the spinal cord?
Brain stem is continuous with the spinal cord
they both contain tracts
79
Name the parts of the **brainstem** (3)
Midbrain
Pons
Medulla Oblongata
80
What are the corpora quadrigemina and what are their functions
four colliculi
* two inferior: visual reflex center
* two superior: auditory reflex center
81
name and give the functio of the (2) pigmented nuclei in the **midbrain**
* **red nuclei:** contrl limb flexion
* **substantia nigra:** sends dopaminergic neurons to basal nuclei to control voluntary movement
82
how many of the cranial nerves have cell bodies located in the brain stem?
10 of 12 cranial nerves (CN3-CN12)
| (all except olfactory and optic)
83
explain why trauma to the brain stem can be fatal
damage to the brainstem = no signals to/from brain = no function of involuntary organs (heart, lungs, etc) = death
84
where does the **decussation of the pyramids** occur and what is the function?
decussation of the pyramids affects contralateral control, occurs over the anterior fissure of the medulla oblongata
85
define **arbor vitae**
network of white matter within gray matter of cerebellum
86
define **vermis**
prominent ridge along the midline of the cerebellum; hold cerebral hemispheres together medially; also called spinocerebellum
87
name the cerebellar lobe that cannot be viewed on the surface of the hemisphere
flocculondular lobe
88
the inability to maintain balance during a tandem walk (heel to toe) due to alcohol intoxication is indicative of impairment of which brain region
cerebellum
89
describe the arrangement of the gray matter and the white matter in the **cerebellum and cerebrum** as well as the **brainstem and spinal cord**
* Cerebellum and cerebrum: inner white matter, outer gray matter
* brainstem and spinal cord: inner gray matter, outer white matter
90
define **spinal dural sheath**
single layered dura mater; has a space between internal surface of vertebral column and dura mater (epidural space)
91
define **filum terminale**
part of the pia mater that supports the spinal cord VERTICALLY
92
Define **denticulate ligaments**
part of the pia mater that supports the spinal cord LATERALLY
93
Define **epidural space**
supports underneath the dura mater layer
94
define **subarachnoid space**
supports underneath the arachnoid mater layer; contains cerebral spinal fluid
95
define **central canal**
runs length of spinal cord and contains cerebral spinal fluid
96
How do the dura mater and pia mater surrounding the **spinal cord** differ from the dura mater and pia mater surrounding the **brain**
Dura mater surrounding the **brain** is double layered; dura mater surrounding the **spinal cord** is single-layered
Pia mater surrounding the **brain** is delicate and attached to the surface of the brain; pia mater surrounding the **spinal cord** is strong and anchors the spinal cord both vertically and laterally
97
What medical condition results from **degeneration of nuclei** in the **ventral horns** in the **spinal cord**?
Amyotrophic Lateral Sclerosis (ALS)
98
transection (damage) of the spinal cord above the cerivical enlargment can cause
quadriplegia (damage to all limbs)
99
How can you tell the difference between paralysis caused by **damage at the level of the precentral gyrus** and **damage at the spinal cord**?
* Damage at the **precentral gyrus:** hemi-paralysis, causing **one side of the body** to be paralyzed
* damage at the **spinal cord:** limb paralysis
100
Autonomic Nervous System function
takes information to the smooth muscles and cardiac muscles (soft organs)
101
Somatic Nervous System function
Takes information to the skeletal muscles (hard organs)
102
list the **sensory receptors** (4)
somatosensory
mechanoreceptors
chemoreceptors
photoreceptors
103
Activation of which division of the Autonomic Nervous System causes dilation of the pupils?
sympathetic
104
Activation of which division of the Autonomic Nervous System causes **constriction** of the pupils?
parasympathetic
105
list (3) major parts of the eye
Tri-layered eye wall
humors
lens
106
What is the function of the lens in the eye?
Reflect and refract light from cornea at the front of the eyeball to the photoreceptors at the back of the eyeball (with the retina)
107
name and describe the (3) layers of the wall of the eye
1. fibrous outer layer: avascular dense regular connective tissue
2. vascular middle layer: composed of anterior iris, middle ciliary body, and posterior choroid
3. sensory inner layer: confined to back of eye (fundus), avascular
108
what structure forms the most anterior part of the eye?
Cornea
109
location and function of the **sclera**
back whites of eyes posterior 5/6 of eye
110
location and function of the **cornea**
front clear of eye, anterior 1/6 of eye
111
location and function of the **pupil**
center of eye, allows light to enter eye
112
location and function of **rods**
black and white vision, dim light
113
location and fuction of **cones**
color vision, bright light
114
location and function of suspensory ligament
holds lense in place
115
location and function of **optic disc**
where the optic nerve runs from back of eyeball (blindspot)
116
location and function of macula lutea
used for hard focus
117
location and function of **fovea centralis**
contains ONLY cones; at center f macula lutea' has highest visual acuity
118
visible colored part of the eye
iris
119
what are the two humors in the eye and their functions?
1. aqueous humor: provides nutrients to avascular cornea/lense; located in anterior segment of eye
2. vitreous humor: supports lense and compresses neural layer against pigmented layer; located in posterior segment of eye
120
which humor in the eye is **formed and drained throughout life**?
which humor is **formed during embryonic development** only?
formed and drained throughout life: **aqueous**
formed during embryonic development only: **vitreous**
121
name and describe the two layers of the sensory layer
outer pigmented layer: absorbs light and develops a clear image
inner neural layer: (aka retina) contains photoreceptors, bipolar neurons, and ganglion neurons
122
name the two types of photoreceptors; which type is more sensitive to light?
**rods** and **cones**
rods are moresensitive to light
123
what happens when **right optic nerve** is severed?
what happens when **right optic tract** is severed?
severed optic nerve: right side blindness
severed optic tract: loss of sight in the left visual field
124
what happens when the **right primary visual cortex** in the **right occipital lobe** is damaged?
partial blidness in both eyes
(primary visual cortex controls both eyes)
125
What is retinal detachment? Explain how retinal detachment can lead to blindness.
When retina separates from blood vessels of the eyeball. Causes blurry vision, incorrect visual signals. The continuous loss of sight will eventually lead to blindness.
126
location and function of the
* lateral geniculate nucleus (LGN)
* supoerior colliculi
* primary visual cortex
* lateral geniculate nucleus: thalamus, visual relay center of brain
* superior colliculi: upport part of the corpora quadrigemina, visual reflex control center
* primary visual cortex: occipital lobe, controls sight ability
127
pathway of light through the eye from the **cornea** to the **photoreceptors**
cornea --\> aqueous humor --\> pupil --\> lens --\> vitreous humor --\> retina --\> photoreceptors
128
the **axons** of which type of **neurons** in the **retina** form the **optic nerve** and generate/transmit **action potentials**?
ganglion cells
129
what is **myopia** and what type of lense is used to correct it?
what is **hyperopia** and what type of lense is used to correct it?
myopia = nearsightedness, concave lense
hyperopia = farsightedness, convex lense
130
list the three major parts of the ear
external ear
middle ear
internal ear
131
name the (3) auditory ossicles in the middle ear
**Malleus** (tympanic membrane)
**Incus**
**Stapes** (oval window)
132
name the (3) parts of the bony labyrinth
**vestibule**
**semicircular canals**
**cochlea**
133
what part of the ear determines **loudness?**
what part of the ear determines **pitch?**
loudness = basilar membrane
pitch = cochlear sterocilia
134
(3) types of cells in a taste bud
basal cells
supporting cells
gustatory cells
135
in which cerebral lobe is the primary gustatory cortex located?
insula
136
name and describe the (3) chemical classes of hormones
1. **Biogenic amine hormones:** derived from TYROSINE; polar, bind to membrane receptors
2. **peptide/protein/glycoprotein hormones:** composed of several amino acids; polar, bind to membrane receptors
3. **steroid hormones:** derived from CHOLESTEROL; non-polar, bind to intracellular receptors
137
name and describe the (2) types of hormone receptors
1. **membrane receptors**: on the plasma membrane surface
2. **intracellular receptors:** within the cytoplasm
138
name and describe the (4) hormone INTERACTIONS with receptors
1. **Classical endocrine interaction:** endocrine gland realease hormone into boodstream which transports it to target cell
2. **Paracrine interaction:** endocrine cell release hormone into interstitial fluid surrounding target cell
3. **Juxtacrine interaction:** endocrine cells are juxtaposed to the target cells in the same organ
4. **Autocrine interaction:** endocrine cells release hormone are the target cells
