Chapter 13 and 14 course packet Flashcards
1
Q
What gives us our physiological distention as humans?
A
The nervous system and the senses
2
Q
What are the 4 areas we need to know for the exam?
A
- The structure and function of the nerve cell
- The overview of the nervous system, with three different levels of organization
- The brain, with a specific list of things to know
- Six specific senses: Somatic, taste, smell, hearing, balance, and vision
3
Q
What are the two kind of cells in the nervous system?
A
- Neurons
2. Neuroglia
4
Q
What is the neurons percent of nervous system volume?
A
Less than or equal to 50%
5
Q
What is the neuroglias percent of nervous system volume?
A
Greater than or equal to 50%
6
Q
What is the neurons percent of nervous system cells
A
≈10%
7
Q
What is the neuroglia percent of nervous system cells?
A
≈90%
8
Q
What is the overall function of the neurons?
A
They conduct the nerve impulses
9
Q
What is the overall function of the neuroglias?
A
They support neuron function
10
Q
What is the input zone of a neuron?
A
The dendrites and cell body
11
Q
What is the conducting zone of a neuron?
A
The axon
12
Q
What is the the trigger zone of a neuron?
A
The axon hillock
13
Q
What is the output zone of a neuron?
A
The axon endings
14
Q
Describe a neuron at rest?
A
The resting membrane potential is ≈ -70 mV. The lipid bilayer of the neuron’s membrane is impervious to charged particles (ions)
15
Q
What is floating within the lipid bilayer of a neuron?
A
Various kinds of proteins that serve as three kinds of ion (sodium or Na+, potassium or K+) channels
16
Q
What are sodium-potassium pump proteins?
A
They are proteins that continuously and actively transport Na+ out of and K+ into the neuron?
17
Q
Some sodium Na+ and potassium K+ diffuse (leak) through all the time
A
Permanently open channel proteins
18
Q
What are gated channel proteins?
A
They are voltage sensitive gates that open with a nerve stimulus
19
Q
What is the action potential?
A
Literally refers to an abrupt, brief reversal “depolarization” in the resting membrane potential across the neural plasma membrane. It moves like a wave down to the axon to the axon endings, this is called the “nerve impulse”
20
Q
At the base of the axon hillock, or trigger zone, the stimulus must reach a specific threshold level in order to generate an action potential. At the threshold, a positive feedback loop of Na+ influx will initiate
A
Threshold level
21
Q
What is all or nothing according to the threshold?
A
If the threshold is reached, a short (≈millisecond) sharp spike of the action potential results, and all action potentials will be identical
22
Q
What is the action potential propagation with the neurons?
A
Once triggered, they spread by themselves (self-propagating) and in only ONE direction: away from the trigger zone. They also do not diminish in magnitude. After ≈millisecond, the gated Na+ channels close, and the resting membrane potential returns “depolarized”
23
Q
What is the effect of myelin?
A
Schwann cells in the peripheral nervous system (PNS), and oligodendrocytes in the central nervous system (CNS)
24
Q
The axon ending (of the presynaptic neuron) has many?
A
Synaptic vesicles filled with neurotransmitter (acetylcholine, serotonin, norepinephrine, dopamine, GABA)
25
They synaptic vesicles fuse with what and what happens?
The plasma membrane, releasing their contents into the synaptic cleft by exocytosis
26
The neurotransmitters cross the synaptic cleft and find what?
Receptor sites on the postsynaptic neuron or effector (muscle or gland cell)
27
When the neurotransmitter binds to postsynaptic receptor it can what effect?
Either an excitatory or inhibitory effect
28
Describe the synaptic integration process
In a multiple synaptic environment like the brain, both excitatory (EPSP's) and inhibitory (IPSP's) can coverage on the postsynaptic neuron and cancel each other out
29
What happens once the postsynaptic neuron fires it's action potential?
The body must rid the synaptic cleft of neurotransmitter in a rapid and controlled fashion
30
How is the rapid and controlled fashion done?
Usually done via: 1) diffusion out of the cleft 2) enzymes released within the cleft break down the neurotransmitter and 3) membrane transport proteins actively pump the neurotransmitter back into the presynaptic neuron or neuroglial cell
31
Overview of the nervous system
1) the nervous system divides into the central nervous system (CNS) and the peripheral nervous system (PNS)
2) the PNS then divides into somatic and autonomic
3) the autonomic then divides into sympathetic and parasympathetic
32
What does the CNS include?
The brain and spinal cord
33
What does the PNS include?
Everything else that conducts nerve impulses outside of the brain and spinal cord
34
What is the somatic subdivision within the PNS?
It deals with things of which you are conscious
35
What is the autonomic subdivision within the PNS?
It deals with things of which you are not conscious of
36
What is the function related to somatic subdivision?
"Conscious" sensory and motor functions
37
What are the organs innervated for somatic subdivision?
Sensory: skin, skeletal muscle and tendons
Motor: skeletal muscle
38
What is the location of the nerve cell bodies for somatic subdivision?
Entirely within the CNS (axons reach all the way to and from organs
39
What is the function related to autonomic subdivision?
"Unconscious" sensory and motor functions
40
What are the organs innervated for autonomic subdivision?
Smooth and cardiac muscle, glands and viscera
41
What is the location of nerve cell bodies for autonomic subdivision?
The neurons that have cell bodies in the CNS are preganglionic neurons, they synapse with postganglionic neurons in the autonomic system ganglia in the PNS
42
Sympathetic autonomic nerves deals with what type of responses?
Fight or flight responses
43
The parasympathetic autonomic nerves deals with what responses?
Ease and feast responses
44
The typical overall response for sympathetic nerves?
Fight or flight
45
The specific responses for sympathetic nerves?
Decrease in glandular secretions (saliva gets thick), GI tract inhibited, sphincters contract, pupils dilate, and an increase in pulse rate
46
What is the typical overall response for parasympathetic nerves?
Ease and feast
47
What are the specific responses for parasympathetic nerves?
Increase in glandular secretions (saliva gets watery), GI tract stimulated, sphincters relax, pupils constrict, decrease in pulse rate
48
What are the neurotransmitter @ effectors for sympathetic nerves?
Norepinephrine
49
What are the neurotransmitter @ effectors for parasympathetic nerves?
Acetylcholine
50
What is the direction of the sensory or afferent nerves?
They bring impulses into the CNS
51
What sends impulses out of the CNS?
Motor or efferent nerves
52
Describe the brain
Approximately 100 billion neurons, weighs approximately 3 pounds; continuous with spinal cord in CNS
53
What are the included structures for the cerebral cortex?
Structures: frontal, parietal, temporal, occipital lobes: in each hemisphere
54
What is the location for cerebral cortex?
The largest structure of human brain, almost covering all of it
55
What is the general function for the cerebral cortex?
Memory, abstract thought, sensory motor, special senses
56
What are the included structures for the thalamus?
Many synapses
57
What is the location for the thalamus?
Centrally located, lateral to 3rd ventricle
58
What is the general function of the thalamus?
Relay station for incoming signals
59
What are the included structures for the hypothalamus?
Nerve cell bodies that release hormones
60
What is the location for the hypothalamus?
Slightly anterior and inferior to thalamus
61
What is the general function of the hypothalamus?
Coordinates nervous and endocrine control
62
What are the included structures for the pituitary gland?
Anterior and posterior lobes
63
What is the location for the pituitary gland?
Hangs from pit. stalk below hypothalamus
64
What is the general function for the pituitary gland?
"Master" endocrine gland
65
What are the included structures for the limbic system?
Hypothalamus, amygdala, hippocampus, part of thalamus and olfactory
66
What is the location if the limbic system?
In the middle of cerebral hemispheres
67
What is the general function of the limbic system?
Integrates memory, base emotions and appetites with cerebrum
68
What is the included structure for the midbrain?
Tectum
69
What is the location of the midbrain?
High brain stem, above pons and cerebellum
70
What is the general function of the midbrain?
Reflex coordination to sight and sound input
71
What are the included structures for the hindbrain?
Pons, cerebellum and medulla oblongata
72
What is the location for the hindbrain?
Brain stem (cerebellum posterior to the brainstem)
73
What is the general function of the hindbrain?
m.o: circulatory and respiratory reflexes;
C: fine motor coordination;
P: bridge between c and cerebrum
74
What are the included structures for RAS (reticular activating system)
Reticular formation
75
What is the location of the RAS?
Interneurons extend from upper spinal cord, through brain stem and into cerebral cortex
76
What is the general function for the RAS?
Controls levels of consciousness: alert, relaxed, drowsy, sleep (slow wave and REM)
77
What are the included structures for the brain cavities and canals?
4 ventricles, aqueducts and canals, meningeal layers
78
What is the location for the brain cavities and canals?
Ventricles within center of CNS, meninges covering the CNS
79
What is the general function of the brain cavities and canals?
CSF-cerebrospinal fluid cushions the CNS from injury and helps to nourish the brain
80
Short term vs. long term memory
A) emotional state
B) time to repeat input
C) association with other memories influence the transfer of short term memory into long term memory
81
Cocaine: blocks the reabsorption of dopamine norepinephrine and other neurotransmitters in pleasure centers
Psychoactive drugs
82
What are the Psychoactive drugs results?
Receptors remain stimulated until all neurotransmitter diffuses out of the synaptic cleft, but without reabsorption, the presynaptic neurons quickly become depleted
83
What is multiple sclerosis?
The progressive destruction of myelin sheaths in CNS neurons
84
What does multiple sclerosis result in?
Numbness, weakness, and lack of body control. Unknown cause, but may be an autoimmune reaction with viral origins
85
What is parkinson's disease?
The onset of deficient levels of dopamine in certain parts of the brain
86
Results from parkinson's disease?
Resulting in a progressive and severe loss of voluntary muscle control. The afflicted lose the ability to learn new skills, yet skill memory is retained
87
What is alzheimer's disease?
The degeneration of neurons in the brain that make and release acetylcholine. The brain skinks and shows a buildup of amyloid protein.
88
What are the results from alzheimer's disease?
Resulting in severe short term memory loss, confusion, paranoid delusions and extreme antisocial behavior. May have genetic predisposition, but ultimate cause unknown
89
Stimulus is?
A specific change to the external or internal environment that the body can detect through sensory receptors
90
Sensation is?
The conscious awareness of a stimulus
91
Perception is?
The understanding of what the sensation means. This involves a conscious interpretation of sensory input by the brain, resulting in some meaning about the external world.
92
What are the types of receptors
Chemoreceptor, mechanoreceptor, photoreceptor, thermoreceptor, nocireceptor or pain
93
What do we need to know about incoming signals?
1) The brain can only interpret action potentials in certain ways (e.g. "seeing stars" when your eye is poked
2) Action potentials do not vary in amplitude, but can have varying firing frequencies
3) As well as varying numbers of receptors and axons firing
94
Describe sensory adaptation
Some receptors have a higher tendency to fire when there is change in environment (i.e, constant stimuli and the action potentials will die off). This phenomenon is more common with chemoreceptors
95
What are some general somatic senses?
Touch, pressure, temperature, pain and muscle sense
96
Describe general somatic senses
1) Includes mechano, thermo, and pain receptors (nociceptors) in skin, skeletal muscles, joints, tendons, and ligaments
2) Signals end up in the primary somats-sensory cortex on the opposite side of the stimulus
97
Pain is the perception of what?
Injury or tissue damage
98
What is somatic pain?
Starts with nociceptor stimuli in the skin, skeletal muscles, joints, and tendons
99
What is visceral pain?
Deals with abnormal conditions in the internal organs (e.g. excessive chemical stimulation, smooth muscle fatigue or spasm)
100
What is referred pain?
Is the phenomenon whereby the brain perceives pain coming from an area different from the actual source (e.g. heart attack, toothache)
101
What are the remaining senses called?
Special senses
102
What does taste (gustatory sense) include?
1) Includes ≈10,000 taste buds, each with 50-150 chemoreceptor cells. Strictly speaking there are only 5 basic "tastes" being sweet, sour, salty, bitter, umami
2) Can distinguish many different tastes because food can have varying degrees of the 5 basic tastes and because of the large role played by the sense of smell in taste perception
103
What are the signals for taste (gustatory sense)?
Signals end up in the parietal lobe
104
Smell (olfactory sense) includes?
Includes ≈10 million olfactory chemoreceptors in the upper part of the nasal cavity, but unlike taste, 1000's of distinct odors can be distinguished
105
Smell (olfactory sense) signals?
Signals enter directly into the olfactory bulbs of the brain (bypasses thalamic relays) and influences the limbic system before being interpreted in the olfactory portion of the cerebral cortex. Thus, olfaction can influence taste, appetite (both gastric and sexual), even emotions. Pheromones in female sweat can result in synchronized menstrual cycles in women who are in regular close contact
106
Hearing (auditory sense) includes?
1) The ear is made up of: outer ear, middle ear, and inner ear
2) Includes vibration-sensitive mechanoreceptors deep within the cochlea called "hair cells of the organ of corti" which sits on a basilar membrane
107
Where do hearing (auditory sense) signals end up?
End up in the auditory cortex of the temporal lobe
108
What receptors detect differences in hearing?
Mechanoreceptors detect not only difference in frequencies, but also amplitude
109
What does balance (equilibrium) include?
1) Continuous with the cochlear duct is the vestibular apparatus made up of the 3 semicircular canals and the utricle and saccule
2) Includes other kinds of hair cells which are also mechano- These together with vision and the somatic senses give us a sense of equilibrium position
110
The three semicircular canals are arranged?
In planes 90 degrees to one another and thus are set up to detect rotational head movements and acceleration and deceleration. At the base of each canal is a capula which contain the hair cell mechanoreceptors
