Nervous System Definitions Flashcards
1
Q
Sensory Nerves
A
Carry messages from the pain receptors in the tip of the finger to the spinal cord.
2
Q
Motor Nerves
A
Carry messages from the spinal cord to a muscle (effector)
3
Q
Association nerves
A
located in the gray matter and connect the sensory nerves to the motor nerves.
4
Q
Reflexes
A
- take place automatically without your having to think about them
- do not depend on the brain, they do depend on the spinal cord
5
Q
Grey matter
A
- Contains mostly: cell bodies, dendrites,and shorty unmyelinated nerve fibres
- Forms outer areas of brain and “H” shaped core of the spinal cord.
6
Q
White matter
A
- Made up of myelinated nerve fibres
- forms some inner regions of the brain and the outer area of the spinal cord
7
Q
Meninges
A
Tough, protection tissue within the skull and spinal column.
8
Q
Cerebellum
A
- part of hindbrain
- involved in unconscious coordination of posture, reflexes and body movements
9
Q
Medulla oblongata
A
- part of hindbrain
- connects brain with spinal cord
- controls: automatic, involuntary responses, such as heart rate, constriction / dilation of blood vessels to control blood pressure, breathing, swallowing, and coughing
10
Q
Pons
A
Relay centre between the neurons of the right and left halves of the cerebrum.
11
Q
Midbrain
A
Relays visual and auditory info between areas of hind brain and forebrain.
> plays an important role in eye movement and control of skeletal muscles.
12
Q
Thalamus
A
- Receives incoming info entering the brain
- correlates processes: including consciousness, sleep, and sensory interpretation.
13
Q
Hypothalamus
A
- controls BP, HR, body temp, and emotions
- regulates and releases certain hormones
14
Q
Cerebrum
A
- Centre for intellect (thinking,problem solving), memory, consciousness, and language.
- interprets and controls response to sensory info.
15
Q
Cerebrospinal fluid
A
- found in the ventricles of the brain and the central canal of the spinal cord.
- transports hormones, WBC, and nutrients across the blood-brain barrier
- acts as a shock absorber to cushion the brain.
16
Q
Cerebral cortex
A
-responsible for language, memory, personality, conscious thought, and other activities associated with thinking and feelings.
17
Q
Corpus callosum
A
-bundle of white matter that joins the two cerebral hemispheres of the cerebrum of the brain; tells opposite side of brain what the other side is doing.
18
Q
Occipital lobe
A
Mainly vision
19
Q
Parietal lobe
A
- receives and processes mainly sensory info
- senses pain and emotions
20
Q
Temporal lobe
A
Auditory reception and hearing.
21
Q
Frontal lobe
A
- voluntary motor movements
- critical thinking, memory, personality
22
Q
Outer ear
A
- air
- contains: Pinna, auditory canal, outside of tympanum
23
Q
Pinna
A
Collects sound
24
Q
Auditory canal
A
Tube that conducts sound waves from the outer ear to middle ear & amplifies sounds waves.
25
Middle Ear
-air
-contains:
>ossicles: 1. Malleus 2. Incus 3. Stapes
>oval window
>Eustachian tube
>round window
26
Tympanum
- elastic structure within the middle ear that vibrates in response to sound waves
- aka ear drum
27
Ossicles
Malleus
Incus
Stapes
28
Oval window
Connective tissue membrane located at the end of the middle ear + beginning of inner ear.
29
Eustachian tube
Equalizes air pressure within the middle ear.
30
Inner ear
- fluids
| - contains: semicircular canals, cochlea,auditory nerve.
31
Cochlea
- used for hearing
| - mechanical energy of sound is converted into electrochemical impulses that are transmitted to the brain.
32
Organ of corti
- Organ of hearing found within the cochlea of the inner ear.
- contains hair cells that detect vibrations in the inner ear and transmits the info to the auditory nerve.
33
Hair cells
Sensory mechanoreceptors attached to the basilar membrane in the organs corti within the inner ear.
34
Semicircular canals
- contains sensors for balance
- three fluid filled loops
- contains mechanoreceptors that detect head and body rotation.
35
Utricle
-sac like cavity in the vestibule of the inner ear; contains sensory receptors for gravitational gravity.
36
Saccule
Saclike cavity in the vestibule of the inner ear; contains sensory receptors for gravitational equilibrium.
37
Otoliths
Detects movement of the head
| Located in the utricle and saccule.
38
Proprioreceptors
-type of mechanoreceptors found in muscles: senses body's position and movements to send info about body position to the brain.
39
Homeostasis
Maintenance of a constant internal environment
| >detection (stimulus) ➡️ integration (receptors) ➡️ response (modulator)
40
Central nervous system
- Brain and spinal cord
| - nerves
41
Peripheral nervous system
-nerves that carry sensory messages to the CNS and send info from the CNS to the muscles and glands
> consists of the autonomic and somatic systems.
42
Neurons
- nerve cell
| - specialized to respond to physical and chemical stimuli
43
Glial cells
- support cell of the nervous system
| - nourishes neurons, removes their waste, defends against infections.
44
Nerve
Message pathway of the nervous systems; made up of many neurons grouped into bundles and surrounded by protective connective tissue.
45
Reflex arcs
A reflex action in response to a stimulus
46
Dendrites
Short, branching terminal on a nerve cell (neuron) that receives signals from other neurons or sensory receptors and relays the impulse to the body.
47
Cell body
- Main part of neuron
| - If sensation received is strong enough it relays it to the axon where an impulses initiated.
48
Axon
- Long, tail like structure in a neuron
| - transmits impulses away from the cell body along its length to the next neuron.
49
Myelin sheath
- Fatty,insulated layer on the axon of a nerve cell
- composed of Schwann cells
- speeds the rate of nerve impulse transmission
50
Membrane potential
Electrical charge separation across a cell membrane a form of potential energy.
51
Resting membrane potential
Potential difference across the membrane and the resting neuron.
52
Polarization
Lowering the membrane potential of the cell below it's equilibrium value and nerves the process of generating a resting membrane potential of of -70 mV
53
Sodium potassium exchange pump
Uses the energy of ATP need to transport sodium ions out and potassium ions into animal cells;important in nerve and muscle cells
54
Depolarization
reducing a membrane potential to less than the resting potential of -70 mV
55
Nodes of Ranvier
- gaps in the Mylan sheath insulating the axon of a myelinated nerve cell
- action potentials the car only at these nodes.
- nerve impulses jump from one node of Ranvier to the next
56
Action potential
- in a axon
- The change in charge that occurs when the gates of the potassium channels close and the gates of the sodium channels open after a wave of depolarization is triggered
57
Threshold potential
The minimum change in the membrane potential required to generate an action potential; usually -55 mV.
58
Repolarization
Return of the nerve to its resting potential following depolarization.
59
Refractory period
The brief time between the triggering of an impulse along an axon and it's readiness of the next impulse; during this time, the axon cannot transmit an impulse.
60
Synapse
Junction between two neurons or between a neuron and effector (muscle or gland)
61
Neuromuscular junction
Synapse between a motor neuron and a muscle cell
62
Neurotransmitter
Chemical messengers greeted by neuron's to carry a neural signals from one neuron to another or from a neuron to an effector
63
Acetylcholine
The primary neurotransmitter of both the somatic nervous system and the parasympathetic nervous system
>acetylcholine excites the muscle cell membrane, causing the flurries Asian contraction of the muscle fiber.
>If remain in the synapse. The muscle fiber Sellwood not repolarization would remain instead of excitation [Contraction].
64
Cholinesterase
Enzyme that breaks down the neurotransmitter acetylcholine in a synapse
65
Dopamine
-Affects the brain synapses in the control of body movements; is willing to sensations of pleasure such as eating
66
Serotonin
Regulates temperature and sensory perception; is involved in mood control.
67
Endorphins
Natural painkiller; also affects emotional areas of the brain
68
Norepinephrine
Opposite of hormone epinephrine which readies the body to respond to fight or flight situations
69
Somatic system
Division of peripheral nervous system that controls voluntary movement of skeletal muscle.
70
Autonomic system
Division of the peripheral nervous system that is under involuntary control; regulates secretions and functions of smooth and cardiac muscle
71
Sympathetic nervous system
- fight / flight
- increase metabolism
- nerve; accelerator
- hormone; adrenaline
72
Parasympathetic nervous system
- normalizes
- decreased metabolism
- nerves; vagus
- hormone; ACh
73
Sensory receptors
- when sensory receptors initiate neural responses, sensation occurs.
- sensation occurs when the neural impulse arrives at the cerebral cortex
74
Sensory adaptation
The process of the brain filtering out redundant, insignificant information
75
Photoreceptors
-rods and cones that absorb light and allow us to sense different levels of light and shades of color.
76
Chemoreceptors
– Stimulated by certain chemicals
| – Nose; old factory cells that detect odours in the air
77
Mechanoreceptors
– Responds to mechanical forces from some form of pressure.
78
Thermoreceptors
– In skin
| – Detect heat and cold
79
Four processes for formation of retinal image:
1. Refraction; bending light rays through mediums
2. Accommodation of lens; -thins: for far vision
3. Adaptation: pupil constriction/ dilation
4. Convergence of eyes: retina records image in same area (fovea)
80
Conduction pathway to visual image area
1. Neurons conduct impulses from rods and cons in retina
2. Optic nerves
3. Optic chiasma
4. Optic tracts
5. Thalamus
6. Cerebrum: occipital lobe
81
Cornea
– transparent part of the sclera
| – Bends light rays into the eye
82
Sclera
- Protects and supports the eyeball
- White and tough protective layer
- external layer
83
Choroid
– Observe scattered light and contains blood vessels
| - intermediate layer
84
Iris
- Colored part of eye
| - regulates the amount of light that enters the eye
85
Pupil
– Opening for light to enter the inner eye
86
Adaptation
- process by which the iris adjust the size of the people based on like conditions, thereby controlling the amount of light that enters
87
Retina
- internal layer of the eye
| - contains photoreceptors: rods & cones
88
Rods
– Peripheral vision
– Light receptors detect black versus white
– Contains rhodopsin: light absorbing pigment
– Vitamin A helps night vision
-sensitive to dim light
89
Cones
```
-stereoscopic vision/clarity
– Fovea
-three types; red, blue and green
– Blind spot; no receptors
-sensitive to different wavelengths of light (color vision)
```
90
Optic nerve
Transmits sensory information to the brain
91
Aqueous humor
– Maintains the shape of the cornea and provides oxygen and nutrients from surrounding cells including those of the lens and cornea.
92
Glaucoma
– condition caused when ducts that drain aqueous humor are blocked; result in high pressure rupturing delicate blood vessels in the eye and results in lack of oxygen and nutrients; can lead to blindness if untreated
93
Vitreous humor
– Maintains shape of eyeball
| -support surrounding cells
94
Lens
Focuses light rays on to fovea centralis
95
Accommodation
Adjustment that the ciliary muscles make to the shape of the lens to focus on objects at varying distances
96
Cataracts
Cloudy or opaque area on the lens caused by the degeneration of protein structure of the lens; prevents the passing of life; increases in size over time and can lead to blindness is not medically treated
97
Astigmatism
Uneven curvature of part of the cornea or lens that results in uneven focus and therefore blurry vision
98
Myopia
– Nearsightedness
- eyeball is too long
- Image falls in front of the retina and is corrected by wearing a concave lens
99
Hyperopia
- results from focused image falling behind the retina and is corrected by wearing a convex lens
- eyeball too short
100
Fovea centralis
Contains a high density of cones and provides acute vision
101
Blind spot
No photoreceptors present
102
Color blindness
An inherited condition that occurs more frequently in males than females, caused by a lack of particular cones, usually red and green
103
What is a bundle of neurons called?
Nerves
104
Tissue
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