Chapter 1: Homeostasis Flashcards
1
Q
Physiology
A
Study of how organisms function
2
Q
Cells
A
The smallest structural unit that can perform all the functions needed for life
3
Q
Cell Differentiation
A
The process to becoming specialized for a task
4
Q
4 Categories of Cells
A
Muscle, Neuron, Epithelial, Connective
5
Q
What cell type are blood vessels considered?
A
Connective Cells
6
Q
Tissue
A
Group of similarity differentiated cells
7
Q
Organ
A
Collection of tissues that work together for the same function
8
Q
Organ System
A
Collection of organs that work together for a common function
9
Q
Muscle Cell Function
A
Transmit force
10
Q
Muscle Cell Types
A
Skeletal, Cardiac, and Smooth
11
Q
Neuron Cell Function
A
To initiate, integrate, and conduct electrical signals
12
Q
Basement Membrane
A
Thin layer of ECM that the epithelial cells sit on
13
Q
Basolateral Side
A
Faces the basement membrane
14
Q
Apical Side
A
Faces the lumen
15
Q
Tight Junctions
A
Fill the space between epithelial cells and have selectively permeable membranes
16
Q
Loose connective tissue
A
loose tissue below the epithelial layer
17
Q
Dense connective tissue
A
Tendon, Ligament, Bone, Adipose
18
Q
Fluid connective tissue
A
Blood
19
Q
ECM [ two functions ]
A
Provides a stable scaffold, transmits chemical messengers cell to cell
20
Q
Ropelike ___ fibers, and rubber band like ____ fibers.
A
Collagen, and elastin
21
Q
Functional Unit
A
Smallest unit with a common function
22
Q
Intracellular Fluid
A
Inside cells, 67% of body fluid
23
Q
Extracellular Fluid
A
Fluid surrounding cells and in blood 20%
24
Q
Interstitial Fluid
A
surrounds cells, but not counting the blood plasma
25
Comparing concentrations between blood plasma and interstitial fluid
about the same
26
5 common physiological variables
blood pressure, body temp, oxygen, glucose, sodium ions
27
Homeostasis
Relatively stable internal conditions
28
Dynamic constancy
Variable may fluctuate in short term, but be averagely stable or predictable in the long term
29
Pathophysiology
A condition giving loss to homeostasis
30
Steady state vs. equilibrium
Both have a constant variable, but equilibrium does not require additional energy to maintain this
31
Negative Feedback System
A system result will reduce the conditions that made it start in the first place
32
How is the production of ATP an example of negative feedback?
As energy is stored in ATP bonds, it slows the enzymes that break down glucose, therefore preventing additional creation of ATP.
33
Example of positive feedback:
Giving birth. Uterine contractions cause release of oxytocin, which further causes more uterine contractions.
34
Set point
The value at steady state for a particular biological variable
35
Clashing demands
Sometimes it is only possible to maintain a set point at the expense of less important set points
36
Why is it a benefit that multiple systems can control a single parameter?
The redundancy allows for the parameter to continue to be regulated in case a disease knocks out one of the systems.
37
Feedforward example
When sensors can sense the body external temperature to proactively start the body warming before it actually starts to cool internally.
38
Reflex
Involuntary built in response to a specific stimulus
39
Reflex Arc Components
Stimulus-->Receptor-->Integrating Center-->Effector-->Response
40
Afferent and Efferent Pathways
Afferent: Sensing the stimulus up to the integrating center
Efferent: From the integrating center to the effector
41
Hormone
Chemical messenger sent normally through blood to another site
42
Local Homeostatic Responses
Response in a local area to a stimulus
43
Neurotransmitters
Transmitted between neurons or to their effectors
44
Paracrine
Transmission within a local neighboring area
45
Autocrine
Signaling of a cell to itself
46
Juxtacrine
Signaling of a cell to another when touching through the membrane
47
Diffusion
Random thermal motion of a molecule
48
Flux Gradient (In General)
Solute particles move from high to low concentration
49
Define "Net flux"
While flux may occur in both directions, net flux is the summation of both directions.
50
Lipid Bilayer is made of:
Phospholipids... with a polar phosphate head group, and a non polar fatty acid chain.
51
What sort of substances can get through the bilayer?
Small non polar molecules, such as O2, CO2, ethanol, fatty acids, steroid hormones
52
What sort of substances cannot get through the bilayer without help?
Large polar molecules such as glucose, or charged ions [Na+,K+,Cl-,Ca2+]
53
What elements of ion channels make them selective?
Size of the pores, and the charge of the channel.
54
What are three ways that channels can be gated?
Chemical, Electrical, Mechanical
55
Define a ligand:
A chemical messenger
56
In what way is a plasma membrane generally charged?
Positive on the inside, and negative on the outside
57
What are the three general types of Mediated Transport?
1) Facilitated Diffusion
2) Primary Active Transport
3) Secondary Active Transport
58
Describe 4 properties of facilitated diffusion:
1) Net flux is down the gradient
2) No energy required
3) Selectivity because of binding sites
4) Transporter can be at saturation due to limited amount of binding sites.
59
What is a primary example of Facilitated Diffusion?
Glucose transport into the body of the cell
60
What is the primary example of the Primary Active Transport?
Na+K+ATPase Pump
61
Before Primary Active Transport, what is the general concentration of K+ and Na+
Intracellular: Low Na+, High K+
Extracellular: High Na+, Low K+
62
PAT step 1:
3 Na+ ions, and ATP attach to the binding sites
63
PAT step 2:
ATP --> ADP, and the channel is opened, and the Na+ goes out of the cell
64
PAT step 3:
2K+ attach to binding sites from outside of the cell, and phosphate is removed, switching the conformation of the channel back to open into the cell, releasing the 2K+
65
Describe 4 properties of Active Transport
1) Flux is against the concentration gradient
2) Energy required
3) Certain selectivity due to binding sites
4) Channel can be saturated due to limited binding sites
66
Intracellular Ion Concentrations
Na+ 15mM, K+ 150mM
67
Extracellular Ion Concentrations
Na+ 145mM, K+ 5mM
68
Describe 4 properties of Secondary Active Transport
1) Against a concentration gradient
2) Energy provided by an ion's gradient
3) Certain Selectivity
4) Transporter saturation
69
What is the usual ion in Secondary Active Transport?
Na+
70
What does it mean for a mediated transport system to saturate?
Since there is a limited amount of channels and binding sites, there is a maximum amount of solute particles that can cross the membrane at a time.
71
Channels in the membrane for water:
aquaporins
72
Can water pass through the lipid bilayer?
Yes because the molecules are small, but they are also polar, and therefore quite slow for any efficient physiological process.
73
Osmolarity
The total solute concentration of a solution
74
Osmole
one mol of solute particles
75
What is the osmolarity of 1 mol of NaCl in 1 liter of water?
2 osmoles/liter
76
What is the general osmolarity of the ECF?
300mOsm
77
What is tonicity?
The concentration of non - penetrating solute
78
What happens to a cell in a hypotonic solution?
The water concentration outside of the cell is greater than inside the cell, therefore water will enter the cell, causing it to expand.
79
What happens to a cell in an isotonic solution?
Nothing. It will retain its volume.
80
What happens to a cell in a hypertonic solution?
The water concentration inside the cell is greater than outside the cell, therefore water will leave the cell, causing it to shrink.
81
Endo and Exo cytosis
When a lipid bilayer is formed around particles that fuse to the membrane either allowing for entrance [endo] or exiting [exo] of solute particles.
82
Functional unit in the Nervous System
nerve cell or neuron
83
Nerve
collection of nerves bound together by connective tissue
84
CNS: Central Nervous System
Brain and spinal cord
85
PNS: Afferent division defintion
sensory cells that send signals AT or TOWARDS the CNS
86
PNS: Efferent division definition
cells that send signals AWAY from the CNS to the periphery
87
Somatic sensory
touch
88
Visceral sensory
organs
89
Special sensory
hear, taste, smell, see
90
Somatic motor
skeletal muscle
91
Autonomic motor: enteric
gi tract
92
Autonomic motor: sympathetic
fight or flight
93
Autonomic motor: parasympathetic
rest and digest
94
Dendrites
incoming receiving branches of neuron
95
Cell body of nerve is also called:
soma
96
Initial segment of nerve cell is also called [2]:
axon hillock, trigger zone; is where the e- starts
97
Axon
Sends signal from soma to axon terminals
98
axon terminals
sends the signal to another nerve cell by neurotransmitters from vesicles
99
What do axon terminals target?
other neurons, muscles, or glands
100
Interneurons
exist in the CNS to integrate information
101
ratio of afferent to inter to efferent neurons
1A=200000 Inter = 10E
102
Presynaptic and post synaptic
self explanatory
103
Glial Cells - 2 types, and where they are found
Nourish and protect neurons:
Oligodendrocytes: CNS
Schwann Cells: PNS
104
How many patches of protection do an oligodendrocyte and schwann cell provide for neurons?
Oligodendrocytes: many
| Schwann Cells: one
105
When measuring membrane potential, readings are usual taken with the reference electrode in the ___ and the recording electrode in the ____.
ECF,ICF
106
The typical resting membrane potential is at:
-70mV
107
Sodium is typically at a higher concentration in the [ECF/ICF]
ECF
108
Potassium is typically at a higher concentration in the [ECF/ICF]
ICF
109
Chloride is typically at a higher concentration in the [ECF/ICF]
ECF
110
Anions are typically at a higher concentration in the [ECF/ICF]
ICF
111
Are there more K+ or Na+ leak channels open at rest?
K+
112
Nernst Equation
E[ion] = 61/Z * log (Co/Ci)
113
Which ion dominates in determining resting membrane potential?
Potassium [K+ is king]
114
At RMP, are there more K+ or Na+ leak channels?
K+ channels
115
At RMP which directions are the K+ and Na+ chemical and electrical gradients?
Potassium chemical gradient is out, electrical is in. Sodium both are into the cell.
116
Even though we have more K+ leak channels, why doesn't the leak out as much?
The resting potential of the cell is already close to the desired potential of K+ [-70 is close to -90].
117
For Type I cells, describe the chloride concentrations
The resting potential for chloride is very similar to -70mV. Also, the membrane is not very permeable to Cl-, therefore the concentration of chloride is relatively equal in the ECF and ICF.
118
For Type II cells, describe the chloride concentrations
There exists minor pumping exchange of Cl- for HCO3-. This creates a slightly less concentration of Cl- inside the cell, therefore via Nernst, the RMP is -76mV for chloride.
119
Depolarization
Going from negative to 0.
120
Overshoot
Going from 0 to positive
121
Repolarizing
Returning from positive to -70mV
122
Hyperpolarizing
Going from -70mV to more negative
123
Ligand gated channel
chemically activated
124
Depolarization [excitatory/inhibitory]
Excitatory
125
Hyper polarization
| [excitatory/inhibitory]
Inhibitory
126
Graded stimulus
Depolarization or hyper polarization proportional to the size of the stimulus
127
During an action potential, which is positive feedback, and which is negative feedback between Na+ and K+?
Sodium is positive feedback, because the more depolarized the cell becomes, the more the sodium channels open, further depolarizing the cell.
128
What is one reason that afterhyperpolarization occurs?
The voltage K+ channels are slow.
129
Absolute refractory period
The cell CANNOT undergo another action potential at this time.
130
Relative refractory period
The cell CAN undergo another action potential, but it takes a stronger stimulus than before.
131
Why does it take a stronger stimulus in the relative refractory period?
Not all the Na+ channels have yet closed, and some of the K+ channels are still open.
132
What is one thing that a refractory period ensures?
One way propagation of signal.
133
What part of the neuron has the highest density of voltage gated Na+ channels?
The axon hillock.
134
What does the myelin sheath do for neurons?
it allows saltatory conduction
135
What is saltatory conduction?
When there is no potential on certain stretches of the axon, therefore charge can jump from one node of Ranvier to another quicker.
136
What property of the axon determines velocity?
The diameter.
137
What are gap junctions?
Places where cells merge like a bridge. conducts electrical signals very quickly and directly,.
138
Where are gap junctions found?
in the heart, smooth muscle, and some brain cells
139
What is the role of Ca2+ in neurotransmitter release?
When the AP reaches the axon terminal, it opens voltage gated Ca2+ channels which enter the neuron and induce exocytosis of the synaptic vesicles. Neurotransmitters are then diffused across the synaptic cleft.
140
What are V snares and T snares?
Little protein chains, [vesicle, and terminal] which bind together on contact with Ca2+ and cause the synaptic vesicles to merge with the post synaptic cell.
141
What is an EPSP?
Excitatory Post Synaptic Potential
142
What are 4 reasons that Postsynaptic potentials are more brief in their depolarization than APs?
1) NT's rapidly bind and unbind from the receptors on the post synaptic cell
2) NT's are taken back during reuptake into the presynaptic terminal
3) NT's can diffuse away from the cells while in the synaptic cleft.
4) NT's can be destroyed by enzymes.
143
What is the typical threshold value?
-55mV
144
Convergence and Divergence of neurons
self explanatory
145
Chloride Type I and how this can be an inhibitory signal
Chloride, while wanting a -70mV RMP will not show a change in RMP, influx of Chloride does keep the cell at 70mV instead of allowing it to move up into an AP.
146
If B is going to C, but A is going to B, what is this called?
Axoaxonal synapse
147
What are three terms that dictate synaptic strength?
Facilitation, Inhibition, and Autoregulation
148
How do drugs modify synaptic strength?
They can affect multiple spots of regulation of neurotransmitters from creation to reception etc.
149
Long Term Potentiation: Function with Glutamate
Some of the glutamate neurotransmitters activate the non-selective AMPA receptors, while some causes Ca2+ influx at NMDA receptors that cause a second messenger system for more glutamate receptors, and the release of Mg2+ that can return to the presynaptic cell and increase the synthesis of glutamate.
150
Neuromodulators are usually made of
small peptides
151
Neuromodulators are usually released...
with NTs
152
Neuromodulators usually activate ___
2nd messenger cascades
153
Frontal Lobe
Thought
154
Parietal Lobe
Speech
155
Occipital Lobe
Sight
156
Temporal Lobe
Sound
157
Cerebrum
contains 4 lobes [frontal,parietal,occipital, temporal]
158
Diencephalon
contains thalamus and hypothalamus
159
Forebrain
contains diencephalon and cerebrum
160
Thalamus
synaptic relay station
161
Hypothalamus
neural and endocrine command center
162
Cerebellum
balance, posture, but not skeletal muscle control
163
White Matter
Contains mostly mylenated axons on the inside of CNS, and outside of spinal cord
164
Gray Matter
Mostly cell bodies and dendrites on the outside of CNS, and the inside of the spinal cord
165
Basal Nuclei
Deep clusters of cell bodies that affect inputs and outputs from the cortex involved in posture and movement
166
Thalamus
Sensory relay station
167
Hypothalamus
Integrator of homeostasis, Master Control. Hormones, autonomic nervous system, feeding and drinking behavior etc.
168
Pituitary gland:
Master gland of the endocrine system. Releases epinephrine and norepinephrine.
169
Spinal Cord: Ventral Horn
Contains cell bodies of efferent neurons
170
Spinal Cord: Dorsal Root Ganglion/ Horn
Contains cell bodies of afferent neurons
171
Spinal Cord: Dorsal Root
Afferent axons
172
Spinal Cord: Ventral Root
Efferent axons
173
Cranial Nerves: Optic
Carries input from receptors in eye
174
Cranial Nerves: Glossopharyngeal
From tongue, auditory tube skin, and carotid baroreceptors --> skeletal muscles involved in swallowing and parotid salivary gland
175
Cranial Nerves: Vagus
From thorax and abdomen to skeletal muscles of pharynx and larynx and smooth muscle and glands of thorax and abdomen. [breathing?]
176
Cranial Nerve: Accessory
Innervates sternocleidomastoid and trapezius muscles in neck.
177
The Spinal Nerves: Neck,arms,hands,shoulders
Cervical [8]
178
The Spinal Nerves: Chest, Upper abdomen
Thoracic [12]
179
The Spinal Nerves: Lower abdomen, hips, legs
Lumbar [5]
180
The Spinal Nerves: Lower GI, genitals
Sacral [5]
181
The Spinal Nerves: Tailbone
Coccygeal [1]
182
Give the other name, and relative sizes of the pre and post ganglionic nerves: Parasympathetic
Craniosacral, pre is large, post is small.
183
Varicosities
Bulges in the axon near the tissue to be signaled. "Crop dusts" the tissue with neurotransmitters.
184
Dual innervation
Organs are connected to both sympathetic and parasympathetic nervous system. Effects are usually opposite, and both are tonically active.
185
Somatic NS: NT and Receptor
Acetylcholine and Nicotinic
186
Autonomic-Para: NT and Receptor
Acetylcholine, Nicotinic and then Muscarinic
187
Autonomic-Sympathetic-NonHormonal: NT and Receptor
Acetylcholine,Nicotinic,Norepinephrine,Adrenergic receptors
188
Autonomic-Sympathetic-Hormonal: NT and Receptor
Acetylcholine,Nicotinic,Epinephrine,Adrenergic receptors
189
Receptor Potential
A graded potential at the peripheral ending of an afferent neuron or on a specialized sensory cell adjacent to an afferent neuron.
190
Where is the first place you can get an AP in the neuron?
The First Node of Ranvier
191
Rapidly Adapting receptor
On and Off, [i.e. clothes pressing on skin]
192
Slowly Adapting Receptor
Continue to fire the whole duration of the stimulus, [i.e. maintaining posture]
193
Describe Sensory Coding
Converting a stimulus energy into a pattern of action potentials to the CNS.
194
Sensory Unit
A single afferent neuron with all of its receptor endings
195
Receptive Field:
are of the body that leads to activity in a particular sensory neuron
196
What does "Adequate Stimulus" mean when referring to sensory coding?
It means "right type", but not necessarily enough strength.
197
What are two ways that intensity is differentiated in primary sensory encoding?
Frequency of action potentials, and by recruitment, where neighboring afferent neurons also are signaled.
198
What is "acuity" when referring to signals?
Precision in localizing a stimulus
199
Labeled Lines
Predetermined pathways that encode for a specific sensation in the CNS. Example, is activating phantom limb.
200
Two point discrimination is better with a [large/small] number of individual sensory neurons, and [larger/smaller] receptive fields
larger number of individual sensory neurons, smaller receptive fields.
201
What can be said about the gradient of receptor fields?
The neuron responds more vigorously when a stimulus is applied in the center of the receptive field because the density is greatest there.
202
Receptive Field Overlap
When different neurons have overlapping receptive fields, the stimulus site can be more accurately determined by the CNS.
203
Lateral Inhibition
When a neuron is excited, it causes an inhibitory response in local neurons so that the stimulus is localized.
204
Ascending Neural Pathways normally consist of how many neurons in the chain?
3. Sensory neuron, labeled line to thalamus or brainstem, then to cerebral cortex
205
One sense does not always go through the thalamus.
Olfactory sense.
206
Association Areas
Final perceptive destination
207
Most nociceptors are [slow/rapid] adapting
slow adapting
208
What neurotransmitter is released usually for nociceptors?
Substance P or Glutamate
209
How do anti-inflammatory drugs work, such as aspirin?
blocks prostaglandin synthesis
210
How do opiates work?
They block ascending synapses to the brain
211
What is TENS?
Transcutaneous Electrical Nerve Stimulation: When you rub a bump after an injury, the somatic receptor activation can stimulate your descending neurons that inhibit transmission of pain
212
What is referred pain?
When your cortex incorrectly senses the location of pain. Often this can be because your visceral and somatic afferent neurons are converging on the same neurons in the spinal cord
213
Where is a heart attack normally felt?
Your left arm or shoulder
214
What can referred pain tell you about?
Which part of your viscera might be damaged.
215
Eye Anatomy: Sclera
White protective eye capsule over all but cornea
216
Eye Anatomy: Cornea
Transparent covering for focusing image
217
Eye Anatomy: Choroid Layer
Dark pigment to absorb light at back of eye
218
Eye Anatomy: Iris
Determines pupil diameter, also gives eye distinct color
219
Eye Anatomy: Ciliary muscle
controls lens shape
220
Eye Anatomy: Zonular Fibers
connect ciliary muscle to lens
221
Eye Anatomy: lens
alters light diffraction by changing shape
222
Eye Anatomy: Macula lutea
No blood vessels here, yellow spot, good for acute vision
223
Eye Anatomy: Fovea Centralis
high color acuity, cones focused here
224
Eye Anatomy: Optic Disc
neurons exit eye to the brain, no photoreceptors, blindspot
225
Eye Anatomy: Aqueous Humor
Anterior fluid compartment between iris and cornea
226
Eye Anatomy: Vitreous Humor
Posterior space filled with jelly substance between lens and retina
227
Which is larger? Refraction at lens or cornea?
Cornea
228
What in general is the accommodation reflex for the eye?
Lens changes shape to account for distance focusing
229
What happens when ciliary muscle contracts?
The zonular fibers are lessened in tension, curving the lens. This is the parasympathetic response
230
What happen when the ciliary muscle relaxes?
The zonular fibers are tightened, flattens the lens. This is the sympathetic response.
231
Why is it considered parasympathetic when the lens is rounded?
It focused in on close things. Focus on your food. Rest and digest.
232
Rounding the lens increases or decreases refraction?
Rounding the lens increases refraction.
233
Myopia [definition,cause, accommodation reflex, optical correction]
Can't see far. Eye too long, focal point before the retina. Accommodation reflex is in reverse, allowing for seeing close objects, optical correction is concave lens that diffracts the light before the cornea so that the usual over focusing occurs right at the retina.
234
Hyperopia [definition,cause, accommodation reflex, optical correction]
You can't see near. The eye is too short, focal point after the retina. Accommodation reflex is normal, rounding the lens focuses earlier right at retina. Optical correction is convex lens that starts to straighten or focus close object earlier so focal point is at retina instead of behind.
235
Presbyopia [cause]
Lens loses flexibility, and cannot round... similar to hyperopia where close up objects cannot be focused.
236
Rods
Sensitive, low acuity, no color vision, located in periphery, 100:1 ratio with ganglia.
237
Cones
Not sensitive, high acuity, color vision, located in fovea centralism, 1:1 ratio with ganglia
238
In the dark: Phototransduction
cGMP high, photoreceptor depolarized, which releases inhibitory information to bipolar cell. No neurotransmitter released to ganglion, therefore no APs to brain.
239
In the light: Phototransduction
cGMP low, photoreceptor polarized, no inhibitory information to bipolar cell. Neurotransmitter released to ganglion, therefore APs to brain.
240
Guanyl Cyclase
Enzyme that creates cGMP constantly
241
cGMP gated channels
opens in response to cGMP allowing entrance of Na+/Ca2+depolarizing the photoreceptor in the dark
242
Photopigment(opsin) and Retinal Unbinding
activated by light
243
Transducin
G-protein turned on by photopigment
244
cGMP phosphodiesterase
Enzyme that breaks down cGMP , cells hyper polarize, turned on by transducin
