Nervous and Endocrine Systems Flashcards
1
Q
What is the difference between Nervous and Endocrine Systems?
A
Nervous: uses electrical and chemical impulses in nerve cells. It’s faster and has pinpoint control (transmits directly to target organ)
Endocrine: uses chemicals released into the bloodstream (hormones)
2
Q
What is the general function of the nervous system?
A
- Sensory Input
(Sensory information is transmitted to the central nervous systems: brain & spinal cord) - Interpretation and Integration of Sensory Information
(Setting priorities on which action to take first) - Motor Output
(responses to sensory information is carried out to effectors which then carry out various actions)
3
Q
What are the three basic structures that serve to function the nervous system?
A
- Receptors
- Neurons (Nerve cells)
- Effectors (muscles/glands)
4
Q
What is the function of receptors?
A
pick up messages through impulses.
5
Q
What is the function of neurons?
A
interprets info from receptors and send instructions to muscles or glands.
6
Q
What is the function of effectors?
A
Carry out the response. Muscles contract. Glands increase/decrease secretions.
7
Q
What is a stimulus?
A
any factor that causes a receptor to trigger an impulse (ex. light, sound…etc.)
8
Q
What is a neuron?
A
The basic unit of structure which function sin the nervous system.
9
Q
what are the three basic parts of the neuron?
A
- Cell Body
- Dendrites
- Axon
10
Q
What is the function of the cell body?
A
Contains the nucleus, cytoplasm and the organelles. controls growth and metabolic activities.
11
Q
What is the function of the dendrites?
A
Receive impulses and conduct them towards the cell body.
12
Q
What is the function of the axon?
A
Carries impulses away from the cell body towards other neurons or effectors.
13
Q
What is a synapse?
A
The junction on the axon which splits into two branches.
14
Q
What is the order the impulse travels through in a neuron?
A
Dendrites—> Cell Body—> Axon
15
Q
What is a Schwann Cell?
A
a living sheath that envelops the axon in neurons (except brain & spinal cord) which is involved in myelin production and also in the regeneration of cut axons.
16
Q
What is myelin, and what does it do?
A
Myelin is a layer of white lipid subsance which forms around the axon. It acts as an insulator which causes myelinated neurons to conduct impulses faster than unmyelinated ones.
17
Q
What is the Neurilemma Sheath?
A
The outer surface of the Schwann Cell.
18
Q
What is the Nodes of Ranvier?
A
Gaps between adjacent Schwann Cells.
19
Q
Where are Schwann Cells mostly found?
A
Peripheral Nervous System.
20
Q
What is multiple sclerosis?
A
A disease of the white matter in the Central Nervous System. Myelin degenerates causing the disruption of electrical impulses.
21
Q
What produces myelin in the central nervous system?
A
Oligodentrocytes
22
Q
What are sensory neurons?
A
Neurons that carry impulses from receptors towards the bran and spinal cord.
(Carry messages about a person’s internal and external environment)
23
Q
What are motor neurons?
A
Neurons that carry impulses from the brain and spinal cord to the effectors
(allows a person to respond to information received)
24
Q
What are interneurons?
A
neurons inside the brain and spinal cord that connect sensory neurons to motor neurons.
25
Which neuron is the most abundant type of neuron?
Interneuron (CNS)
26
Which neurons make up the Peripheral Nervous System?
Motor and Sensory
27
What are the charges of the resting neuron?
Outside (net Positive)
| Inside (net Negative)
28
What does polarized mean?
the neuron's cell membrane has opposite charges on either side. Caused by an unequal distribution of ions.
29
What is the ratio of ions in the resting neuron?
Outside (3Na+)
| Inside (2K+)
30
What is the resting neuron?
When the neuron is at rest (not conducting impulses)
31
What is membrane potential?
The separation of charges
32
How is resting potential achieved?
The sodium-potassium pump maintains equilibrium by pumping 3Na+ out, and 2K+ in.
33
What is depolarization?
the process when the outside becomes negative, and the inside becomes positive.
34
How is depolarization achieved?
When an impulse is initated, the membrane becomes permeable to sodium ions, which enter the cell rapidly, causing the inside to become net positive.
35
What is action potential?
The temporary reversal of the resting potential.
36
What is repolarization?
As the adjacent section becomes depolarizaed, the preceding section returns back to its resting state.
37
What is propoagation?
Self-gernation.
38
How does repolarization occur?
Na+ gates close, and K+ gates open.
K+ ions move out and the interior becomes negative again.
Sodium-potassium pump restores the balance of Na+ and K+ reverting it back to resting potential.
39
What is the stages that occurs in the neuron membrane, after a stimulus?
Resting Potential--> Depolarization ---> Action Potential --> Repolarization --> Resting Potential.
40
What is a Threshold Level?
The level of intensity a stimulus must pass in order to generate a response.
41
What is an all-or-none response?
The neuron fires, or it doesn't.
42
What is the refractory period?
The period of time where the neuron cannot transmit another impulse until repolarization occurs.
43
What factors does the rate at which the impulse travels on depend on?
1. Diameter of the axon.
(larger diameter = faster conduction)
2. Degree of Myelination
(Myelinated axons conduct impulses faster)
44
What is Salatory conduction?
Occurs in myelinated neurons where the impulse "jumps" from one node of Ranvier to the next. Action potential only occurs at the nodes of ranvier.
45
What two ways can the strength of a stimulus be measured?
1. stronger stimulus causes more frequent impulses along the neuron.
2. Strong stimulus causes more neurons to be stimulated. (threshold level of many neurons is reached)
46
What are synaptic knobs?
Swollen tips at the branches of the Synapse.
47
What do the synaptic knobs contain?
Synaptic vesicles which contain neurotransmitters inside.
48
what is the travel path of an impulse (at the synaptic knob)?
Presynaptic Neuron ---> Synaptic Cleft ---> Postsynaptic Neuron.
49
What is the transmission sequence from the synaptic knobs?
1. Nerve impulse reaches the synaptic knobs
- Ca2+ channels open in the presynaptic membrane.
- Calcium ions cause the synaptic vesicles to fuse with the presynaptic membrane.
- neurotransmitters are released into the synaptic cleft through exocytosis.
- neurotransmitters diffuse across the clef and bind to receptors on the postsynaptic membrane.
2. Neurotransmitters and the receptors bind cause the sodium gates to open and Na+ to move in.
- depolarization occurs and the impulse is generated.
3. Excess neurotransmitters are removed, sodium gates close and repolarization occurs.
50
What are two ways in which neurotransmitters are removed?
1. Reuptake
- neurotransmitteres are taken back by the presynaptic neuron through active transport. (except acetylcholine)
2. Enzymatic Breakdown
- enzyme breaks down the neurotransmitter and the fragments are reabsorbed by the presynaptic membrane through active transport.
51
What is the most common neurotransmitter and it's enzyme?
Neurotransmitter: Acetylcholine
Enzyme: Acetylcholinesterase
52
What is another common neurotransmitter?
Norepinephrine
53
What is an excitatory Impulse?
An impulse that depolarizes, but does not reach an action potential in order to carry out the impulse.
54
What in an inhibitory synapse/impulse?
When the neurotransmitter causes the postsynaptic membrane to be hyperolarized (membrane permeable to K+) which inhibits transmission of impulses.
55
What is summation?
The production of an action potential as a result of a stimuls from 2 or more neurons.
56
What is included in the Central Nervous System?
-Brain and Spinal Cord
57
What is the function of the central nervous system?
To coordinate and control activities.
58
What is included in the Peripheral Nervous System?
1. Somatic Nervous System
| 2. Automatic Nervous System
59
What is the function of the Somatic Nervous System?
VOLUNTARY ACTIONS.
| Sensory neurons bring info to CNS.
60
What is the function of the AUTONOMIC nervous system?
INVOLUNTARY ACTIONS.
1. SYMPATHETIC DIVISION prepares the body for emergency and stress.
2. PARASYMPATHETIC DIVISION returns the body to normal.
61
What is the central nervous system protected by?
Brain is protected by the CRANIUM.
| The spine is protected by the VERTEBRAL COLUMN.
62
What is the 3 protective membranes between the bone and the CNS tissue called?
Meninges.
63
What is the cerebrospinal fluid and what does it do?
It is the fluid that circulates within the brain and spinal cord. it:
1. absorbs shock to cushion the brain.
2carries out circulatory function.
64
What three things is the brain very sensitive to?
1. Oxygen deficiency
2. Lack of Glucose
3. High temperatures.
65
What is the BLOOD-BRAIN-BARRIER?
A selective mechanism that maintains a stable chemical environment for the brain.
66
What is the function of the MEDULLA OBLONGATA?
controls involuntary activities such as breathing, heart rate and blood pressure.
67
What is the function of the PONS
acts as a relay centre and connects the medulla with the upper parts of the brain.
68
What is the function of the CEREBELLUM?
Coordinates skeletal muscle movement and maintains balance.
| Processes info from eyes, ears, muscles and joints about body position.
69
What is the function of the HYPOTHALAMUS?
Helps maintain homeostasis.
70
What is the Cerebrum?
The largest part of the brain consisiting of the right and lefft CEREBRAL HEMISPHERES
Connected by a bridge of tissue called the CORPUS CALLOSUM..
71
What two layers make up the cerebrum?
1. Cerebral Cortex (gray matter)
| 2. White Matter (myelinated neurons)
72
What four lobes is each cerebral hemisphere divided into and what are their functions?
1. FRONTAL LOBES (voluntary movements, personality, speech, thought)
2. TEMPORAL LOBES (hearing and memory of auditory and visual experiences)
3. PARIETAL LOBES (processes sensory information such as touch, pain and pressure)
4. OCCIPITAL LOBES (sensory areas associated with vision)
73
What is the function of the HIPPOCAMPUS?
Functions to transfer short-term memory into long-term memory.
74
What does the left side of the brain control?
Speech, logic, calculations, writing and mathematics.
75
What does the right side of the brain control?
spatial perception, artistic, musical, emotions and imagination.
76
What are the two main functions of the spinal cord?
1. connects the nerves of the peripheral nervous system with the brain.
2. Controls certain reflexes that do not require supervision by the brain.
77
What is a reflex arc?
When an effector responsds to a stimulus without brain coordination.
78
Does the Cranial Nerves and Spinal nerves belong to the PNS?
Yes.
79
What is the VAGUS NERVE?
An important CRANIAL NERVE which carries impulses to many internal organs.
80
What are the two types of reflexes?
1. MONOSYNAPTIC REFLEX (involves motor and sensory neurons, but no interneurons)
2. POLYSNAPTIC REFLEX (Involves interneurons, motor neurons and sensory neurons)
81
What is the process of a reflex arc?
1. Receptor is triggered
2. Passes to sensory neuron
3. Passes to interneuron
4. Passes to motor neuron
5. Reaches effector/muscle
6. Passes to spinal cord/white matter
7. Reflex occurs
82
What three structures protect the eye?
1. Eyelids
2. Conjunctiva (transparent membrane)
3. Lacrimal Glands (produce water fluid)
83
What are the three layer of the eye?
1. Sclera (OUTER white layer of the eye)
2. Choroid (MIDDLE layer)
3. Retina (INNER layer)
84
What is the function of the Cornea?
Allows light to enter the eye, also causes the bending of light rays.
85
What is the function of the choroid?
Absorb light and prevent light from bouncing around. Also contain blood vessels that nourish eyes.
86
What regulates the diameter of the pupil and how?
The Choroid.
Bright light--> contraction of circular muscles---> constricts pupils
Dim light---> contraction of radial muscles--> dilate pupils
87
What does the retina contain?
1. Fovea (site of sharpest vision)
| 2. Photoreceptors.
88
Where is the aqueous and vitreous humour?
Aqueous--> in front of lens
| Vitreous--> Behind the lens.
89
What are the two light receptors?
1. Rods (black and white vision, contain rhodopsin)
| 2. Cones (Colour, fine print. contain blue, green or red light pigmentation)
90
What is different about the blind spot?
Contain no rods or cones.
91
What is the process of vision?
Light--> nerve cells--> Receptor cells--> Impulses--> Receptor cells--> Nerve cells--> Optic Nerve
92
Parts the ear.
1. Outer Ear (gas)
2. Middle Ear (gas)
3. Inner Ear (liquid)
93
What structures are in the Outer ear and what are their functions?
Auditory Canal (collects sound waves and channels them to the eardrum)
94
What structures are in the Middle ear and what are their functions?
1. Timpanic membrane contains Ossicles that amplify sound by 20X)
2. Eustachian Tube (Equalizes the pressure on both side s of the tympanic membrane. Connects the middle ear to the pharynx)
95
What are the structures in the inner ear and what are their functions?
```
OVAL WINDOW (vibrations of the ossicles pass through here)
2. COCHLEA (receive sound and the ORGAN OF CORTI, hair cells, move and create impulses.
```
96
What is the pathway of sound?
1. Sound waves--> auditory canal--> vibration of tympanic membrane.
2. middle ear (ossicles) amplify sound--> Oval Window
3. Fluid in cochlea vibrates--> Organ of Corti move--> Impulse
4. Impulse--> Sensory neurons--> auditory nerve--> temporal lobe
97
What are two ear organs involved in balance and equilibrium?
1. Utrical and Saccule which contain small calcium carbonate rocks called OTOLITHS
2. Semicircular Canals (maintain balance)
98
What is the endocrine system made up of?
Ductless Glands that secret e hormones to target cells.
99
What are the two types of glands?
1. Exocrine Glads (produce secretions which reach their destination through ducts/tubes
2. Endocrine Glands (Release secretions, hormones, directly to the blood stream.
100
What are the 2 types of hormones?
1. Steroid Hormones (lipid-like, Trigger DNA to produce certain proteins)
2. Protein (Peptide) Hormones (Made up of amino acids, can not be taken orally. Activate enzymes which change cell production.)
101
What is Negative Feedback?
effect of returning a condition to normal value. Allows us to maintain Homeostasis.
102
What is Positive Feedback?
Destablizing Effect, builds up, does not result in homeostasis.
103
What does the thyroid gland secrete?
Thyroxine and Calcitonin.
104
What is the function of Thyroxiene?
To regulate the body's metabolic rate.
105
What is Hyperthyroidism?
excess secretion of thyroxine. causes weight loss, sweating and high blood pressure.
106
What is hypothyroidism?
Undersecretion to thyroxine, causes retarded growth.
107
what is the secretion of thyroxine regulated by?
TSH (Thyroid stimulating hormone) and Hypothalamus.
108
What does the thyroid need to produce thyroxine?
Iodine.
109
What is the function of calcitonin?
Lower blood clacium levels by inhibitng calcium.
110
What are parathyorid glands?
4 tiny oval glands embedded in the bak o the thyroid gland?
111
What do parathyroid glands secrete and what is its function?
Secrete Parathyroid hormone (PTH) which raise calcium levels (opposite of Calcitonin)
112
What are the three target tissues of PTH?
1. Bones (release clacium)
2. Kidneys (Conserve clacium loss in urine)
3. Intestines (absorb more calcium)
113
What is a tetany and what is it caused by?
When neurons depolarize without stimulus. CAused by deficiency of PTH
114
What structure is both an exocrine and endocrine gland?
Pancreas.
115
What does the endocrine portion of the pancreas do?
the Islets of Langerhands of the pancreas secrete two hormones:
1. Beta cells (secrete insulin)
2. Alpha cells (secret glucagon)
116
What is the function of insulin?
Lowers blood sugar levels.
117
What is the function of glucagon?
raise blood sugar levels.
118
What is diabetes mellitus?
A disease resulting form the undersecretion of insulin.
119
What are the adrenal glands?
Paired glands on top of the kidneys. Contain the outercortex and inner medulla.
120
What two hormones does the adrenal medulla secrete?
1. 80% epinephrene
| 2. 20% norepinephrine.
121
What is the function of the adrenal cortex?
Responsds to endocrine (pituitary) signalsy
