Nervous and Endocrine Systems Flashcards
(264 cards)
1
Q
What is the basic functional and structural unit of the nervous system?
A
Neuron
2
Q
What are action potentials?
A
electrochemical signals of the nervous system
3
Q
What is the soma?
A
central cell body
it contains the nucleus and is where most of the biosynthetic activity of the cell takes place
4
Q
Neurons have ___ axon and ___ dendrites.
A
one
many
5
Q
Neurons with one dendrite are termed _____, and those with many dendrites are ______.
A
bipolar
multipolar
6
Q
What direction does an action potential travel?
A
in one direction, dendrites receive the information and the axons carry it away from the cell body
7
Q
Axons terminate into ______ _____.
A
synaptic knobs- which form connections with target cells
8
Q
What happens when an action potential reaches the synaptic knob?
A
chemical messengers are released and travel across a very small gap called the synaptic cleft to the target cell
9
Q
What is the difference between a neuron and a nerve?
A
neuron- single cell
nerve- large bundle of many different axons from different neurons
10
Q
What is anterograde movement in neurons?
A
from the soma to the axon terminus
11
Q
What is kinesin?
A
protein motor that drives movement of vesicles and organelles along microtubule in axons
12
Q
What is the resting membrane potential?
A
-70 mV
electric potential across the plasma membrane, the interior is negatively charged with respect to the exterior
13
Q
What two membrane proteins are required to establish the resting membrane potential?
A
Na+/K+ ATPase
K+ leak channels
14
Q
The Na+/K+ ATPase pumps __ sodium ions out of the cell and __ potassium ions into the cell with the hydrolysis of one ____ molecule.
A
3
2
ATP
15
Q
What form of transport is carried out by the Na+/K+ ATPase?
A
primary active- uses ATP to drive transport against gradient
16
Q
What do potassium leak channels allow?
A
allow only K+ to flow out of the cell down their gradient, they are open all the time
17
Q
Why is the resting membrane potential negative?
A
one extra sodium is being pumped out compared to the potassium coming in and the leak channels allow K+ to flow out
18
Q
Are neurons the only cells with resting membrane potentials?
A
no all cells have it but they are unique in that they use it to generate action potentials, muscle cells also do this
19
Q
What would happen to the resting membrane potential if potassium leak channels are blocked?
A
it becomes less negative because K+ is stuck in the cell
20
Q
What would happen to the resting membrane potential if sodium ions were allowed to flow down their concentration gradient?
A
it would become less negative and possibly positive because more sodium ions would flow into the cell
21
Q
What is depolarization?
A
change in membrane potential from -70 mV to a less negative or even positive number
22
Q
What is repolarization?
A
returns the membrane potential to normal
23
Q
Why is the cell polarized?
A
it is negative on the inside and positive on the outside
24
Q
What do the voltage gated sodium channels allow?
A
they open in response to a change in membrane potential and allow sodium ions to flow down their gradient into the cell to depolarize it (less negative or positive)
25
What is the threshold potential?
-50 mV
| threshold needed for an action potential to generate
26
What happens when threshold is reached? below?
the sodium channels are opened fully allowing sodium ions to rush in, down its gradient to depolarize that section of the membrane to about +35 mV before inactivating
below threshold, channels are closed not allowing passage of anything
27
How does depolarization move down the axon?
when one part of the membrane is depolarized, the part next to it gets slightly depolarized until it reaches threshold, in this way it passes it down the axon
28
If an action potential starts at one end of an axon, can it run out of energy and not reach the end?
no, action potentials are continually renewed at each point in the axon, once it starts it will propagate without changing amplitude until it reaches a synapse
29
What will happen to the voltage gated sodium channels when the membrane potential goes from -70 to -60?
none of the channels will open because it has not reached threshold of -50 mV, its all or nothing
30
What happens in the process of repolarization?
1. voltage gated sodium channels inactivate very quickly shutting off flow of sodium ions into the cell
2. voltage gated potassium channels open more slowly and stay open longer, as potassium leaves the cell the membrane potential return to negative numbers overshooting resting potential down to -90 mV, then the channels close
3. potassium leak channels and Na+/K+ ATPase function to bring back to resting membrane potential
31
What would be the effect if voltage gated potassium channels were inhibited?
the membrane potential would still be repolarized but it would take a lot longer
32
If a toxin prevents voltage gated sodium channels from closing, what will happen?
- voltage gated potassium channels will open but not close - they normally close by repolarization
- membrane will not repolarize to normal
33
What creates the myelin sheath?
Schwann cells from the PNS
| Oligodendrocytes in CNS
34
Would an axon be able to conduct action potentials if its entire length were wrapped in myelin?
no because no ion can enter or exit where there is myelin
35
Nodes of Ranvier?
periodic gaps in myelin sheath where voltage gated sodium and potassium channels are concentrated
36
How does the myelin sheath speed up conduction of action potentials?
by forcing the action potentials to jump from node to node (saltatory conduction)
37
Is the amount of energy consumed by Na+/K+ ATPase more in myelinated or unmyelinated axons?
more in unmyelinated because it has to maintain the resting potential in the whole membrane whereas in myelinated axons it only has to maintain resting potential in the nodes of Ranvier
38
What is equilibrium potential?
no net movement of ions across the membrane
39
What is the equilibrium potential of sodium?
+50 mV
| no more sodium can come in at this point
40
What is the equilibrium potential for potassium?
-90 mV
| it is too negative that K+ cannot escape the attraction so potassium is driven in
41
Are there more potassium or sodium leak channels?
potassium because the resting potential is closer to the K+ equilibrium potential
42
What is the refractory period?
short period of time when the neuron is unresponsive to membrane depolarization
43
What is the absolute refractory period?
a neuron will not fire another action potential no matter how strong a membrane depolarization is induced
voltage gated sodium channels are inactivated and will not open again until resting membrane potential is reached and the channels have returned to closed
44
What is the relative refractory period?
a neuron can be induced to transmit an action potential but the depolarization required is greater than normal because the membrane is hyperpolarized
45
What causes hyperpolarization?
caused by the voltage gated potassium channels not closing yet
46
If voltage gated potassium channels shut more quickly after repolarization than normal, how would this affect the refractory period?
absolute- not affected because it is due to the inability of sodium channels to open
relative- would be shorter
47
What is a synapse?
junction between the axon terminus and the dendrites, soma, or axons of a second neuron
could also be axon to organ
two types: electrical and chemical
48
Electrical synapse?
occur when the cytoplasm of two cells are joined by gap junctions so action potentials spread directly from one cell to another
common in smooth muscle and cardiac muscle
49
Chemical synapse?
found at the end of axons where they meet their target cells, action potential is converted into a chemical signal
50
What are the 8 steps in a chemical synapse?
1. Action potential reaches the end of an axon, the synaptic knob
2. Depolarization of the presynaptic membrane opens voltage gated calcium channels
3. Calcium influx into the presynaptic cell causes exocytosis of neurotransmitter stored in secretory vesicles
4. Neurotransmitter molecules diffuse across the narrow synaptic cleft
5. Neurotransmitter binds to receptor proteins in the postsynaptic membrane, these receptors are ligand gated ion channels
6. the opening of these ion channels in the postsynaptic cell alters the membrane polarization
7. If the membrane depolarization of the postsynaptic cell reaches the threshold of voltage gated sodium channels, an action potential is initiated
8. Neurotransmitter in the synaptic cleft is degraded and/or removed to terminate the signal
51
What is a common example of a chemical synapse?
neuromuscular junction between neurons and skeletal muscle
52
What neurotransmitter is released in the neuromuscular junction?
acetlycholine (ACh)
53
What degrades ACh after a synapse?
acetylcholinesterase (AChE)
54
What are some neurotransmitters?
Gamma-aminobutyric acid (GABA)
Serotonin
Dopamine
Norepinephrine
55
If a neurotransmitter, such as ACh, opens a channel that depolarizes the postsynaptic membrane, it is _____.
excitatory
56
Neurotransmitters that induce hyperpolarization are _____.
inhibitory
57
What ultimately determines the effect on the postsynaptic cell?
the receptor and its associated ion channels
neurotransmitters can be excitatory and inhibitory depending on the receptors
58
A presynaptic neuron can release ____ type of neurotransmitter and the postsynaptic neuron can respond to ____ neurotransmitters
one
many
59
If a neurotransmitter causes the entry of chloride into the postsynaptic cell, is it excitatory or inhibitory?
inhibitory
| chloride is negative so it will make the potential more negative making it harder to reach threshold
60
If an inhibitor of acetylcholinesterase is added to a neuromuscular junction, what will happen with the postsynaptic membrane?
it will be depolarized longer, acetylcholinesterase is not there to degrade ACh so the sodium channels will remain open longer
61
What causes unidirectional signaling at synapses between neurons?
only the postsynaptic cell has receptors for neurotransmitters
62
What is summation?
adding the effect of all the impinging synapses on a nuron, add the stimuli
63
Excitatory postsynaptic potentials (EPSP)?
excitatory neurotransmitters cause postsynaptic depolarization
64
Inhibitory postsynaptic potentials (IPSP)?
inhibitory neurotransmitters cause these
65
Temporal summation?
presynaptic neuron fires action potentials so rapidly that the EPSPs and IPSPs pile up on top of each other
EPSP- additive effect is enough to reach threshold depolarization required to start postsynaptic action potential
IPSP- postsynaptic cell will hyperpolarize, inhibiting action potentials
66
Spatial summation?
All EPSPs and IPSPs from all the synapses on the postsynaptic cell are summed at any give time, if threshold is reached an action potential will fire
67
What are two types of effectors?
muscles and glands
68
What happens in a reflex?
a sensory neuron transmits an action potential to a synapse with a motor neuron in the spinal cord which causes an action to occur, brain is not involved
69
What happens in the muscle stretch reflex?
- long sensory neuron detects stretching of muscle
| - signal is transmitted to a motor neuron cell body in the spinal cord, causing muscle to contract
70
What is a reflex involving two neurons and one synapse?
monosynaptic reflex arc
71
Inhibitory interneuron?
short neuron which forms an inhibitory synapse with a motor neuron causing a muscle to relax (ex. hamstring in knee reflex)
72
Reciprocal Inhibition?
concurrent relaxation of the hamstring and contraction of the quads is an example
73
If a reflex occurs without the involvement of the brain, how are we aware of the action?
1. sensory neuron also branches to form a synapse with a neuron leading to the brain
2. other sensory info is received after the action is taken
74
Somatic division of the PNS?
concerned with conscious sensation and deliberate, voluntary movement of skeletal muscle
75
Autonomic division of the PNS?
involuntary process such as digestion, metabolism, circulation, perpiration
76
Two subdivisions of the autonomic?
Sympathetic (fight or flight)
| Parasympathetic (rest and digest)
77
What are some effects of the parasympathetic system?
- Gland and motility (digestion) stimulation
- relaxation of sphincters
- bladder contraction (enables urination)
- constriction of airways
- decreased heart rate
- constriction of pupils
- near vision accommodation
- erection/ lubrication
78
What are some effects of the sympathetic system?
- Gland and motility (digestion) inhibition
- contraction of sphincters
- bladder relaxation (inhibits urination)
- relaxation of airways (opens)
- increased heart rate and blood flow
- sweating and blushing
- pupil dilation
- far vision accommodation
- release of epinephrine
- ejaculation/orgasm
79
The majority of cell bodies are found in the ____.
CNS
80
Cell bodies bunched together in the CNS are called _____. Bunched cell bodies in the PNS are called _____.
nuclei
| ganglia
81
Other names for the three subdivisions of the brain:
Hindbrain?
Midbrain?
Forebrain?
Rhombencephalon
Mesencephalon
Prosencephalon
82
What is the function of cerebrospinal fluid?
shock absorption for brain
| exchange nutrients and waste in CNS
83
What is the spinal cord responsible for?
- relay info to and from brain
- simple spinal reflexes (ex. deep tendon reflex)
- primitive processes like walking, urination, and sex organ function
84
What does the hindbrain consist of?
medulla, pons, cerebellum
85
Function of Medulla?
- control autonomic processes such as blood pressure, heart rate, respiratory rate, swallowing, vomiting
- controls reflex reactions such as coughing or sneezing
- relays sensory info to cerebellum and thalamus
86
Function of Pons?
- controls antigravity posture and balance
- connects the spinal cord and medulla to upper regions of brain
- relays info to cerebellum and thalamus
87
Function of Cerebellum?
- integrating center
| - coordination of complex movement, balance and posture, muscle tone, spatial equilibrium
88
Function of Midbrain?
- integration of visual and auditory info
- visual and auditory reflexes
- wakefulness and consciousness
- coordinates info on posture and muscle tone
89
Function of Thalamus?
- relay center for somatic sensation
| - relays info between spinal cord and cerebral cortex
90
Function of Hypothalamus?
- controls homeostatic functions (temp regulation, fluid balance, appetite) through neural and hormonal regulation
- controls primitive emotions such as anger, rage, sex drive
- controls pituitary gland
91
Function of Basal Nuclei?
- regulate body temp and muscle tone
- coordination of learned movement patterns
- general pattern of rhythm movements (walking)
- subconscious adjustments of conscious movements
92
Function of Limbic system?
- controls emotional states
- links conscious and unconscious portions of the brain
- help with memory storage retrieval
93
Function of Cerebral Cortex?
- four lobes with subfunctions
- conscious thorough processes and planning, awareness and sensation
- intellectual function (intelligence, learning, reading, communication)
- abstract thought and reasoning
- memory storage and retrieval
- initiation and coordination of voluntary movement
- complex motor patterns
94
Function of Corpus Callosum?
connects left and right cerebral hemisphers
95
What makes up the brainstem?
Medulla, Pons, Midbrain
96
What is the diencephalon?
thalamus and hypothalamus
97
What is included in the forebrain?
Diencephalon
| Telenchephalon
98
Left vs Right side?
Left- motor functions of right side of body, dominant, speech
Right- motor of left side, visual and spatial reasoning, music
99
Function of Frontal Lobe?
initiates all voluntary movement and are involved in complex reasoning skill and problem solving
100
Function of Parietal Lobes?
general sensations (touch, temp, pressure, vibration) and gustation (taste)
101
Function of Temporal Lobes?
process auditory and olfactory sensation and involved in short term memory
102
Function of Occipital Lobes?
process visual sensation
103
How many pairs of cranial nerves? spinal nerves?
12
| 31
104
Cranial nerves convey sensory and motor info to and from the _____. Spinal nerves convey to and from the ____.
brainstem
| spinal cord
105
What is the effect the Vagus nerve has on the heart and GI tract?
decreases heart rate and increases GI activity (part of parasympathetic system)
106
All somatic motor neurons innervate what cells? Use what neurotransmitter? Where does it have cell bodies?
- skeletal muscle
- ACh
- in the brain stem or ventral portion of spinal cord
107
All somatic sensory neurons have a _____ dendrite extending from a sensory receptor toward the soma, which is located just outside the CNS in a _____ _____ _____.
long
| Dorsal Root Ganglion
108
What is a dorsal root ganglion?
bunch of somatic and autonomic sensory neuron cell bodies located dorsal to the spinal cord, there is a pair for every segment of the spinal cord
109
The dorsal root ganglia is protected within the vertebral column but is outside the ______.
meninges so it is outside the CNS
110
The efferents of the autonomic consist of what two neurons?
preganglionic- cell body in the brainstem and spinal cord, sends axon to autonomic ganglion outside spinal cord
postganglionic- outside spinal cord, sends axon to effector (smooth muscle or gland)
111
All autonomic preganglionic neurons release what neurotransmitter?
ACh
112
All parasympathetic postganglionic neurons release what neurotransmitter?
ACh
113
Almost all sympathetic postganglionic release what neurotransmitter?
norepinephrine (NE, adrenaline)
114
Location of preganglionic soma in sympathetic? parasympathetic?
Thoracolumbar
Craniosacral
115
Preganglionic axon in sympathetic (long or short)? Parasympathetic?
symp- short
para- long
116
Which ganglia is close to the cord but far from the target? (sympathetic or para)
sympathetic
117
Which ganglia is far from cord but close to the target? (sympathetic or para)
parasympathetic
118
Postganglionic axon in sympathetic (long or short)? para?
symp- long (NE)
para- short (ACh)
119
Where is the adrenal gland located?
above the kidneys (one for each kidney)
120
Why is the adrenal cortex important?
endocrine gland that secretes glucocorticoids (cortisol) and mineralcorticoid (aldosterone) and some sex hormones
121
The adrenal medulla is part of the ____ nervous system.
sympathetic
it is derived from sympathetic postganglionic neurons and is directly innervated by sympathetic preganglionic neurons
122
Upon activation of the sympathetic system, the adrenal gland is stimulated to release _____.
epinephrine (adrenaline-slightly modified NE)
123
T/F
| Epinephrine is a hormone.
True
it is released into the bloodstream by a ductless gland
124
What are some effects of epinephrine?
- very rapid, short lived
- sudden flushing and sweating when severely startled
- stimulation of the heart
- generally the same as effects of sympathetic system
125
How does the brain know the difference between stimulation of visual receptors and olfactory receptors?
based on which sensory neurons are signaling
126
Exteroceptors?
sensory receptors that detect stimuli from the outside world
127
Interoceptors?
receptors that respond to internal stimuli (baro, chemoreceptors, blood pressure, pH)
128
Mechanoreceptors?
respond to mechanical disturbances (ex. Pacinian Corpuscles detect pressure deep in the skin)
129
Why is an auditory hair cell important?
mechanoreceptor found in the cochlea of the inner ear that detects vibrations caused by sound waves
130
Why are vestibular hair cells important?
mechanoreceptor located in semicircular canals and inner ear that detect acceleration and position relative to gravity
131
Chemoreceptors?
respond to particular chemicals
ex: olfactory receptors- detect airborne chemicals and allows us to smell things
gustatory receptors- taste buds
autonomic chemoreceptors in walls of arteries respond to changes in arterial pH
132
Nociceptors?
- pain receptors stimulated by tissue injury
- generally nerve endings that detect chemical signs of tissue damage
- can be somatic or autonomic
- autonomic- dull aching pain (referred pain)
133
Thermoreceptors?
detect changes in temp (autonomic and somatic)
134
Electromagnetic receptors?
- stimulated by electromagnetic waves
| - only example is rods and cones in eyes(photoreceptors)
135
The nervous system is programmed to respond to ______ stimuli.
changing
136
T/F
| Nociceptors do not adapt.
True
137
Proprioception?
awareness of self in space, body part position
138
Muscle spindle?
- mechanoreceptor
- example of proprioception
- detects muscle stretch in deep tendon reflex
139
What portion of the CNS requires input from proprioceptors?
cerebellum because it coordinates movement
140
What can taste buds detect?
```
sweet (glucose)
salty (Na+)
bitter (basic)
sour (acidic)
umami (amino acids and nucleotides)
```
141
Information from taste is transmitted to the brain by what?
cranial nerves
142
Why do smells bring back vivid memories?
olfactory bulbs are located near centers of the brain important for memory
143
What makes up the outer ear?
auricle (pinna) and the external auditory canal
144
What divides the middle ear from the outer ear?
tympanic membrane
145
What three bones comprise the middle ear?
malleus
incus
stapes
146
What divides the middle and inner ear?
oval window
147
What structures make up the inner ear?
cochlea
semicircular canals
utricle
saccule
-important for balance
148
What is the round window?
membrane covered hole in the cochlea near the oval window which releases excess pressure
149
What is the Eustachian tube?
auditory tube, passage from back of throat to middle ear which functions to equalize pressure on both sides of eardrum, is the cause of ear popping
150
Summary from sound to hearing?
sound waves -> auricle -> external auditory canal -> tympanic membrane -> malleus, incus, stapes -> oval window -> perilymph -> endolymph -> basilar membrane
-> auditory hair cells -> tectorial membrane -> neurotransmitters stimulate bipolar auditory neurons -> brain -> perception
151
Sound vibrations are first conveyed as air and turn into what?
bone and then liquid
152
What is the organ of Corti?
basilar membrane, hair cells, tectorial membrane it is the primary site where auditory stimuli are detected
153
What distinguishes pitch?
regions of the basilar membrane vibrate, stimulating auditory neurons
basilar membrane is thick (detect high pitch) near the oval window and thin near apex of cochlea (low pitch)
154
What distinguishes loudness of sound?
amplitude of vibrations
larger vibrations cause more frequent action potentials
155
If a sensory neuron leading from the ear to the brain fires an action potential more rapidly, how will the brain perceive this change?
this would indicate increase in volume of sound
156
If the auditory nerve is severed, can sound still be detected by conductance through bone?
no
157
If the bones of the middle ear are unable to move, would this impair the detection of sound by conductance through bone?
they are not involved directly in detecting sound, bone conductance can still stimulate the cochlea and result in hearing
158
What are semicircular canals filled with?
three tubes filled with endolymph
159
What do semicircular canals detect?
rotational acceleration of the head
160
What innervates semicircular canals and where do they send info?
afferent neurons
| send balance info to pons, cerebellum
161
What do the utricle and saccule do?
located in inner ear and monitor static equilibrium and linear acceleration
162
Where is the image formed in the eye?
retina
163
What acts as a lens for the eye?
cornea, light is refracted as is passes through
| refractory index higher than air
164
What is the white of the eye?
sclera
165
What is beneath the sclera?
choroid- absorbs excess light
166
What is contained in the anterior chamber (just inside cornea)?
aqueous humor
167
What is at the back of the anterior chamber?
- iris (colored) with an opening called the pupil
| - muscles in iris regulate pupil diameter
168
What is behind the iris?
- posterior chamber contain aqueous humor
| - back of posterior chamber is the lens (fine tunes light to focus on retina)
169
What varies the curvature of the lens?
ciliary muscle
170
What does light pass through to get from the lens to the retina?
vitreous chamber which contains vitreous humor (thick)
171
What does the retina contain to detect light?
rods and cones (photoreceptors)
172
What do rods and cones synapse with?
nerve cells called bipolar cells (one axon and one dendrite)
173
What do bipolar cells synapse with after rods and cones?
ganglion cells whose axons comprise the optic nerve to the occipital lobe
174
What is the optic disk?
blind spot (contains no photoreceptors), point on retina where axons from ganglion converge to form the optic nerve
175
What is macula?
part of the retina that contains fovea centralis (focal point) which contains only cones for extreme visual acuity
176
What do special pigment proteins contained in rods and cones do when light hits them?
changes tertiary structure while absorbing light
177
Retinal?
in rods and cones derived from vitamin A
178
In the dark, what is retinal like?
several trans double bonds and one cis
179
When retinal absorbs a photon of light what happens?
it is converted to all trans form which triggers a series of reactions
180
What is responsible for night vision?
rods- more sensitive to dim light and more concentrated in the periphery of the retina
181
What are cones responsible for?
require light and are responsible for color vision and high acuity vision, more concentrated in fovea
182
What physical difference allows cones to absorb different colors?
each type of cone makes a particular pigment protein which is specialized to change conformation when light of the appropriate frequency strikes it
183
Emmetropia?
normal vision
184
Myopia?
nearsightedness, too much refraction at the lens or an abnormally long eyeball results in focal length that is too short
185
Hyperopia?
farsightedness, too little refraction at the lens or an abnormally short eyeball results in focal length that is too long
186
What can fix myopia?
concave (diverging) lens
187
What can fix hyperopia?
convex (converging) lens
188
Presbyopia?
inability to focus (accommodate), results from loss of flexibility of the lens, aging
189
What is the signal of the endocrine system?
hormones, can work over days, not always rapid like action potentials
190
Hormone?
molecule which is secreted into the bloodstream by an endocrine gland (ductless), and which has its effects upon distant target cells possessing the appropriate receptor
191
Hormone receptor?
polypeptide that possesses a ligand specific binding site
192
What determines tissue specificity of hormone action?
whether the cells of a tissue have the appropriate receptor
193
Autocrine?
modifies the activity of the cell which secreted them (T cell secretes interlukin 2 which stimulates increased activity of the same T cell)
194
Two classes of hormones?
hydrophilic- peptides, amino acid derivatives, bind to cell surface
hydrophobic- steroid hormones, bind to cell interior
195
Peptide hormones?
synthesized in rough ER and modified in Golgi, stored in vesicles until needed, released by exocytosis, cannot cross membrane because hydrophilic
196
How do peptide hormones communicate with the interior of the cell?
second messenger cascade
197
Are peptide hormones rapid?
yes because they modify the activity of existing enzymes in cytoplasm, duration is brief
198
Two subgroups of peptide hormones?
polypeptide
| amino acid derivatives
199
Example of polypeptide hormone?
insulin
200
Example of amino acid derivative hormone?
tyrosine
201
Where are steroid hormones synthesized?
from cholesterol in the smooth ER
202
How do steroid hormones reach the bloodstream once made in the cell?
they diffuse right through the membrane in the stream because of hydrophobicity
203
How do steroid hormones travel through the bloodstream?
they stick to plasma proteins like albumin
204
What holds steroid hormones bound to plasma proteins?
hydrophobic interactions
205
How do steroid hormones exert its effects on the target cell?
diffusing through the plasma membrane to bind with a receptor in the cytoplasm
206
What do steroid hormones do after binding to the its receptor in the cell?
the complex enters the nucleus to regulate transcription to change amount of proteins in the cell, effects are slow (days to weeks)
207
T/F
| Regulation of Endocrine system is preplanned.
False
| hormone levels rise and fall depending on needs
208
Tropic hormones?
hormones that regulate hormones
209
Most feedback in the endocrine system is _____.
negative
210
What portion of the brain controls much of the endocrine system?
Hypothalamus, releases tropic hormones to regulate, it controls the anterior pituitary
211
Hypothalamic pituitary(hypophysial) portal system?
mini circulatory system for efficient transport of hypothalamic factors straight to the anterior pituitary
212
What are portal systems?
two capillary beds in sequence, allowing for direct communication of nearby structures
-ex. hypothalamic pituitary, hepatic
213
Another name for anterior pituitary? posterior?
adenohypophysis
neurohypophysis
214
What is the posterior pituitary composed of?
axons which descend from the hypothalamus, these neurons are an example of neuroendocrine cells (neurons which secrete hormones into the bloodstream)
215
Are hormones in the posterior pituitary made by axon termini or somas in the hypothalamus?
somas and are transported down the axons
216
Is epinephrine secreted by a duct into the bloodstream?
No, endocrine hormones are not secreted through ducts
217
Would an inhibitor of protein synthesis block the action of thyroid hormone?
yes because it binds to a receptor that regulates transcription
218
Would the production of ATP by mitochondria be stimulated or repressed by thyroid hormone?
stimulated because thyroid hormone stimulates basal metabolic rate throughout the body consuming more ATP so mitochondria would have to make more ATP
219
Would thyroid hormone affect isolated mitochondria directly?
no, it affects mitochondria indirectly
220
What type of hormone does the Hypothalamus secrete?
releasing and inhibiting factors (peptides)
221
What is the target of hormones secreted by hypothalamus?
- anterior pituitary
| - modifies activity
222
What hormones does the Anterior Pituitary secrete?
- Growth (GH, peptide)
- Prolactin (peptide)
- Thyroid Stimulating Hormone (TSH, peptide, tropic)
- Adrenocortiocotropic (ACTH, peptide)
- Luteinizing (LH, peptide, gonadotropic)
- Follicle Stimulating (FSH, peptide)
223
What is the target of Growth Hormone (GH)?
- increase bone and muscle growth
| - increase cell turnover rate
224
What is the target of Prolactin?
- mammary gland
| - milk production
225
What is the target of TSH?
- thyroid
| - increase synthesis and release of thyroid hormone
226
What is the target of ACTH?
increase growth and secretory activity of adrenal cortex
227
What is the target of LH?
- ovary/ovulation
| - testes/testosterone synthesis
228
What is the target of FSH?
- ovary/follicle development
| - testes/spermatogenesis
229
What is secreted by the posterior pituitary?
- Antidiuretic Hormone (ADH, vasopressin, peptide)
| - Oxytocin (peptide)
230
What is the target of ADH?
- kidney/water retention
- increases blood volume
- increases blood pressure
231
What is the target of Oxytocin?
- breast/ milk letdown
| - uterus/ contraction
232
What is secreted by the Thyroid gland?
- Thyroid hormone (TH, thyroxine, modified amino acid)
| - Calcitonin (thyroid C cells, peptide)
233
What is the target of TH?
- Child: necessary for physical and mental development
| - Adult: increase metabolic rate and temp
234
What is the target of Calcitonin?
- bone, kidney
| - lowers serum (Ca 2+)
235
What is secreted by the parathyroids?
Parathyroid Hormone (PTH, peptide)
236
What is the target of PTH?
- bone, kidney, small intestine
| - raises serum (Ca 2+)
237
What is secreted by the Thymus?
Thymosin (children only, peptide)
238
What is the target of Thymosin?
T cell development during childhood
239
What is secreted by the Adrenal Medulla?
Epinephrine (modified amino acid)
240
What is the target of Epinephrine?
sympathetic stress response (rapid)
241
What is secreted by the Adrenal Cortex?
- Cortisol (glucocorticoid, steroid)
- Aldosterone (mineralcorticoid, steroid)
- Sex steroids
242
What is the target of Cortisol?
- longer term stress response
- increase blood glucose
- increase protein catabolism
- decrease inflammation and immunity
243
What is the target of Aldosterone?
- kidney
| - increase Na+ reabsorption to increase blood pressure
244
What is secreted by the Endocrine Pancreas (islets of Langerhans)?
- Insulin (beta cells secrete, peptide, absent or ineffective in diabetes mellitus)
- Glucagon (alpha cells secrete, peptide)
- Somatostatin (SS, sigma cell secrete, peptide)
245
What is the target of Insulin?
- Decrease blood glucose
| - increase glycogen and fat storage
246
What is the target of Glucagon?
- increase blood glucose
| - decrease glycogen and fat storage
247
What is the target of Somatostatin?
inhibits many digestive processes
248
What is secreted by testes?
testosterone (steroid)
249
What is the target of testosterone?
- male characteristics
| - spermatogenesis
250
What is secreted by ovaries/placenta?
- Estrogen (steroid)
| - Progesterone (steroid)
251
What is the target of Estrogen?
- female characteristics
| - endometrial growth
252
What is the target of Progesterone?
- endometrial secretion
| - pregnancy
253
What hormone is secreted by the Heart?
atrial natriuretic factor (ANF, peptide)
254
What is the target of ANF?
- kidney
| - increase urination to decrease blood pressure
255
What hormone is secreted by the Kidneys?
erythropoietin (peptide)
256
What is the target of Erythropoietin?
- bone marrow
| - increase red blood cell synthesis
257
In humans, vision is due to stimulation of what type of receptor?
electromagnetic
258
What is the correct order of events during synaptic transmission?
1. action potential reaches end of axon
2. voltage gated calcium channels open
3. Neurotransmitter binds to ligand gated ion channel
4. Neurotransmitter in synaptic cleft is degraded
259
Which of the following hormones has its receptor located on the cell surface?
Renin
TH
Oxytocin
Aldosterone
Oxytocin
| -any hormone that is a peptide
260
What could hyperparathyroidism cause?
1. enhance breakdown of bone by osteoclasts and release of Ca 2+ into the bloodstream (weak bones, Increased serum calcium levels)
2. enhance reabsorption of calcium in nephrons of kidneys
3. enhance absorption of calcium in small intestine
261
Which would alter gene expression by regulating DNA transcription?
Glucagon
Insulin
Pepsin
Cortisol
Cortisol
| -anything that is a steroid hormone
262
High blood pressure can be rectified by what?
- decrease in Aldosterone
| - ACE (angiostein converting enzyme) inhibitors
263
In which region of the brain is the hippocampus located?
temporal lobe
264
What are three normal calcium functions in the cell?
1. memory acquisition and storage
2. release of synaptic vesicles from the cytoskeleton at the axon terminal
3. release from the sarcoplasmic reticulum to aid in muscle contraction
