Bio 315 exam2 PDF

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Bio 315 Exam 2 ( w/johnson) Study online at quizlet.com/_3rs7n2 1.

Nervous Tissue

Cells are densely packed and intertwined

2.

Neurons

-transmit electrical signals

3.

Support cells

-non-excitable -Surround and wrap neurons -Several functions

4.

The Neuron

- cells that connects the bodys communtication system

5.

action potentials

8.

Neuron Cell Body : -Densely packed, flattened sacs of Nissl Bodies rough ER and free ribosomes -Stain darkly -Renew membranes of the cell/make proteins

9.

Dendrites

-Extensively branching from the cell body -Transmit electrical signals toward the cell body -Function as receptive sites

10.

axons

-produce and conduct action potentials -transmit impulses away from the cell body

Specialized cells that conduct electrical impulses along the plasma membrane 6.

action potential facts

a. Longevity - can live and function for a lifetime

what do axons contian?

12.

axon hillock

b. Do not divide - fetal neurons lose their ability to undergo mitosis; neural stem cells are an exception (hippocampus, olfactory bulb) c. High metabolic rate - require abundant oxygen and glucose

7.

11.

1. Neurofilaments, actin microfilaments, and microtubules a. Provide strength along length of axon b. Aid in the transport of substances to and from the cell body -- Axonal transport

Synapses

-Initial segment of the axon - it generates action potenitals 13.

terminal branches

- neurons for these as sites of communication between cells

- branch at the end of the axon

14.

axon terminals

20.

presynaptic neuron

-axon ends in knobs (end bulbs) 15.

multipolar

-conducts signal toward a synapse

-more than two processes; usually many dendrites and one axon 16.

21.

postsynaptic neuron

-transmits electrical activity away from a synapse

22.

axodendritic

-between axon terminals of one neuron and dendrites of another

23.

axosomatic

between axons and neuronal cell bodies

24.

axoaxonic

uncommon types of synapses

25.

synaptic vesicles

bipolar

-two processes that extend from opposite sides of the cell body 17.

-membrane bound sacs containing neurotransmitters -present in axon terminal

unipolar

26.

action potnetials

27.

neuroglia

electrical signals

-one process that emerges from cell body and divides like an inverted letter T 18.

Synapses

-Elaborate cell junctions -Signals pass across synapse in one direction

19.

neurotransmitters

-chemical messengers

usually only refers to supporting cells in the CNS 28.

astrocytes

-most abundant glial cell type -take up and release ions to control the environment around neurons

29.

microglia

-part of the CNS's defense system -smallest and least abundant

30.

phagocytes

-the macrophages of the CNS -engulf invading microorangisms and dead nureons

31.

ependymal cells

-help produce cerebral spinal fluid (CSF) -line the brain ventricles and central cavity of the spinal cord;bear cilia-help regulate the cerebrospinal fluid

32.

oliodnederocytes

-have few branches -wrap their cells processes around axons in CNS -form the myelin sheaths in the CNS -one coils around several different axons

42.

white matter arrangement

tracts only in the CNS

43.

rostral

toward the nose

44.

caudal

toward the tail, or away from the head

45.

afferent neurons

information toward the CNS -sensory neurons picking up the sensory information

46.

efferent neurons

information away from the CNS -motor neurons going out to the rest of the body

47.

interneurons

located totally within the CNS -synapse with sensory neurons (connects the different parts)

33.

satellite cells

surround sensory neuron cell bodies within ganglia of PNS

34.

Schwann cells

-surround axons in the PNS -form myelin sheath around axons of the PNS

48.

sensory signals

picked up by sensory receptors -carried by afferent nerve fibers of PNS to the CNS

35.

myelin sheaths

-segmented structures composed of the lipoprotein myelin -form insulated layer to prevent leakage of electrical current increase the speed of impulse conduction (50x)

49.

motor (efferent) signals

are carried away from the CNS -innervate muscles and glands

50.

somatic body region

outside of ventral body cavity -body wall, trunk muscles, and limbs

51.

visceral body region

inside of ventral body cavity, including glands -all of the structures inside, like the organs

52.

somatic sensory

senses found in the somatic sensory region -has both general and special somatic senses

53.

general somatic senses

receptors are widely spread around the body -modalities: touch, pain, vibration, pressure, and temperature,

54.

special somatic senses

receptors restricted o the head -hearing, vision, smell, equilibrium

55.

proprioceptive senses

detects senses in tendons and muscle, also joint position found in the general somatic senses

56.

visceral sensory

generally seven modalities

57.

general visceral senses

stretch, pain, temperature, chemical changes, nausea, and hunger -felt in the digestive, urinary, and reproductive organs

58.

special visceral

-sense taste

59.

somatic motor system

signals of contraction of skeletal muscles -under voluntary control

36.

multiple sclerosis (MS)

37.

Nodes of Ranvier

autoimmune disease is the degeneration of myelin=weakness, difficulty walking, vision disturbances

-gaps along the axon between the Schwann cells that wrap around the axon -jumps from node to node which makes it travel a lot faster -myelin sheath one Schwann cell, which is many sheaths along the axon 38.

unmyelinated

-thin axons -conduct electrical signals more slowly -still supported by Schwann cells but do not form sheaths

39.

gray matter

-cell bodies, dendrites, axon terminals --everything except the axons themselves

40.

white matter

myelinated axons

41.

gray matter arrangement

-nuclei= clusters of neuron bodies in CNS -ganglia=clusters of neuron cell bodies columns=rows of neuron cell bodies cortex= continuous sheet (only cerebrum and cerebellum

60.

61.

visceral motor system

-regulates the contradiction of smooth and cardiac muscle, secretions by glands -makes autonomic nervous system -controls function of visceral organs -"involuntary nervous system"

nerves

-cordlike organs in the peripheral nervous system -consists of numerous axons wrapped in connective tissue

62.

nerve fascicles

63.

endoneurium

groups of axons bound into bundles

layer of delicate loose connective tissue surrounding each axon 64.

70.

rootlets

come off the spinal cord that are arranged continuously

71.

dorsal rami

form each spinal nerves innervates a horizontal strip of skeletial muscle and skin on dorsal side of axial region

72.

ventral rami

innervate anterior thorax, abdomen, and limbs

73.

dermatome

an area of skin innervated by spinal nerves

74.

trunk of dermatome

innervated by cutaneous branches of different plexus

75.

upper limb of dermatome

supplied by nerves of the brachial plexus

76.

lower limb of dermatome

lumbar nerves- anterior surface -sacral nerves - posterior surface and buttocks

77.

exteroceptors

sensitive to stimuli arising from the outside of the body -located at or near the body surface

78.

interoceptors

perineurium

(visceroceptors) receive stimuli from internal viscera -monitor a variety of stimuli

connective tissue wrapping surrounding a nerve fascicle; dense irregular 65.

connective tissue

66.

epineurium

79.

proprioceptors

monitor degree of stretch -located in the musculoskeletal organs

80.

muscle spindles

-they are in the muscle organ -there are numerous ones and they determine stretch

81.

golgi tendon organs

found in the tendons -not in the cell, but in the tendon

82.

joint receptors

monitor the degree of movement in joints

83.

receptor cells

specialized cells; either modified epithelial cells or modified neurons -synapse with sensory neurons

84.

somatic motor neurons

-control muscle cells -large myelinated -cell bodies in ventral gray matter of spinal cord

85.

motor unit

one motor neuron and all of the muscle cells it innervates

...

whole nerve is surrounded by tough fibrous sheath; -sense irregular connective tissue 67.

spinal nerves

31 pairs, contain thousands of nerve axons

68.

dorsal root

contains sensory neurons -cell bodies located in the dorsal root ganglion

69.

ventral root

contains motor neurons arising from gray column

86.

neuromuscular junction

synapse between a motor neuron and a muscle fiber -one neuromuscular junction per muscle cell

87.

motor end plate

axon terminal plus specialized region of muscle cell membrane

88.

nerve plexuses

-network of nerves -primarily serve the limbs -axons from ventral rami crisscrosses

89.

prosencephalon

the forebrain -divides into the telencephalon and diencephalon (secondary vesicles)

90.

mesencephalon

the midbrain -remains undivided

91.

rhombencephalon

the hindbrain -divides into metencephalon and the myelencephalon

92.

telencephalon

develops into the cerebral hemishperes

93.

diencephalon

develops into the thalamus, hypothalamus, and epithalamus (including pineal gland)

94.

mesencephalon

103.

subdural space

-potential space between dura and arachnoid mater

104.

subarachnoid space

filled with CSP -contains the blood vessels that supply the brain

105.

arachnoid villi

allow CSF to pass into the dural blood sinuses

106.

pia mater

-delicate loose connective tissue layer -clings tightly to the surface of the brain

107.

ventricles of the brain

-filled with cerebrospinal fluid (CSF) --extracellular fluid of central nervous system

108.

lateral ventricles

located in cerebral hemispheres (divided) first and second ventricles

109.

third ventricle

lies in the diencephalon -connected with lateral ventricles by interventricular foramen

110.

cerebral aqueduct

connects 3rd and 4th ventricles- lies in the midbrain

111.

fourth ventricle

-lies in the pons and medulla oblongata -connects to central canal of the spinal cord -continuous with subarachnoid space via median and two lateral apertures

112.

cerebrospinal fluid

provides a liquid cushion for the brain and spinal cord -brain floats in CSF --formed in choroid plexuses -returned to blood in dural sinuses

113.

blood-brain barrier

-prevents most blood-borne toxins from entering the brain -not an absolute barrier -tight junctions between endothelial cells in brain capillaries

114.

spinal pathways

central column of gray matter -dorsal/ventral horns; h-shaped

115.

lateral white matter

composed of myelinated and unmyelinated axons

116.

ascending axons

sensory pathways; dorsal tracts

117.

descending

motor pathways; ventral tracts

118.

1st order neurons

sensory neurons

119.

2nd order neurons

interneurons in spinal cord

120.

3rd order neurons

interneurons in thalamus to cerebral cortex

121.

decussation

pathways that cross-over

122.

contralateral side

information from one side crosses over to other side

develops into the midbrain 95.

metencephalon

divides into the pons and cerebellum

96.

myelencephalon

divides into the medulla oblongata

97.

brain stem

consists of the midbrain, pons, and medulla oblongata

98.

gyri (gyrus)

ridges

99.

sulci (sulcus)

grooves

100.

meninges

fibrous membranes that cover the brain -covers and protects the CNS -enclose and protects the vessels that supply the CNS -contain the cerebrospinal fluid -has the dura, arachnoid and pia mater

101.

102.

dura mater

arachnoid mater

-strongest of meninges -dense irregular connective tissue -periosteal layer-against the skull -meningeal layer-two layers fused to enclose the dural sinuses -beneath the dura mater

123.

ipsilateral side

remains on same side; no crossing

136.

primary somatosensory

124.

dorsal column pathway

3 neurons in series -touch, pressure, conscious proprioception •

Brodmans area #1-3

137.

Brodmans area #5,7

sensory associations

138.

Brodmans #4

primary motor

139.

Brodmans #6

pre-motor

140.

association axons

communications between different areas on same hemisphere

141.

commissural axons

communication between different hemispheres

142.

primary motor cortex

somatic motor area, located in precentral gyrus

143.

pyramidal cells

large neurons of primary motor cortex

144.

motor homunculus

body map of the motor cortex

145.

somatotopy

body is represented spatially in many parts of the CNS -neurons to different body regions remain separated in the CNS

146.

premotor corext

-receives processed sensory information -controls voluntary actions dependent on sensory feedback -involved in the planning of movements

147.

primary somatosensory cortex

-located in postcentral gyrus -involved with conscious awareness of general somatic senses

148.

spatial discrimination

-precisely locates a stimulus

149.

sensory homunculus

-a body map of the sensory cortex

150.

sensory association areas

-cortical areas involved in conscious awareness of sensation -located in parietal, temporal, occipital lobes and insula

1st order neurons enter spinal cord and ascend to medulla (no synapse until medulla oblongata) • Synapse with 2nd order neurons in medulla; decussate and travel to thalamus • 3rd order neurons from thalamus to primary somatosensory area of cerebral cortex processed to consciousness Spinothalmic pathways spinothalmic pathways

-three neurons -pain, temperature, non-discriminative touch

126.

1st order neurons in spinothalmic pathways

synapse with 2nd order neurons in dorsal horns of the gray matter in the spinal cord

127.

2nd Order neurons in spinothalmic pathways

immediately decussate in spinal cord and ascend to thalamus

128.

Spinocerebellar pathways

-two neurons -proprioception to cerebellum -modifies body movements;needs to know the positions of body parts

125.

descending motor pathways

deliver motor instructions from the brain to the spinal cord

corticospinal (pyramidal)

-precise and skilled voluntary movement -synapse on somatic motor neurons in ventral horns in the cord -most decussate in medulla as they descend

131.

other descending pathways (extra pyramidal)

-unconscious, course, and postural movements -decussate in pons

151.

somatosensory association area

-brodmann's #5,7 -integrates different sensory inputs (touch, pressure, and others) -draws upon stored memories of past sensory experiences

132.

cerebral hemispheres

accounts for 80% of brain mass

152.

caudate nucleus

arches over the thalamus

133.

transverse fissure

separates cerebrum and cerebellum

153.

lentiform nucleus

lens shaped

134.

longitudinal fissure

separates cerebral hemispheres

154.

globus pallidus

subdivision of the lentiform nucleus

135.

cortex gray matter

-home of our conscious mind -be aware of ourselves -communicate, remember, and understand -controls movements -sensory perceptions

155.

putamen

subdivision of the lentiform nucleus

129.

130.

156.

157.

basal nuclei functions

the limbic system

-receive in...