Exam 1 Flashcards
(124 cards)
1
Q
Homeostasis
A
-Maintenance of internal conditions in face of external perturbations
-maintaining a dynamic steady state of internal environment
-normal set point for physiologic parameters
2
Q
Homeostatic control
A
- Body detects deviations from normal
- Integrate information with needs of the body
- Respond by adjusting or adapting to restore homeostasis
3
Q
Homeostatic control can be ___ or____
A
Local, systemic
4
Q
Homeostatic control is always
A
Coordinated by feedback/feedforward loops
5
Q
Homeostatic factors
A
-pH
-Fluid volume and pressure
-Temperature
-H2O, salt/electrolytes
-Waste products
-O2 and CO2
-Nutrients
6
Q
Negative feedback loop
A
- Sends a signal back to the stimulus, reducing the intensity of the stimulus
- Bringing the body closer to homeostasis
7
Q
Examples of negative feedback loops
A
- Appetite
– Hormones
– Blood glucose
– Thermoregulation (at the level of the skin)
8
Q
Positive feedback loops
A
-Sends a signal back to the stimulus, increasing the intensity of the stimulus
-Pushes the body farther away from homeostasis, as a means to an end
9
Q
Examples of positive feedback loops
A
• Parturition
• Hormones
• Blood clotting
• Lactation
10
Q
Feedforward loops
A
• An anticipatory response
– Precedes a stimulus
– Can be preventative
11
Q
Examples of feedforward loops
A
– Salivation
– Motor control
– Anxiousness
– Lactation
12
Q
What do cells do?
A
• Acquire things (uptake)
• Build things (synthesis)
• Converts things (metabolism)
• Reproduces (proliferates)
• Dies (apoptosis)
13
Q
Nucleus
A
– Control center
– Houses DNA
– Site of transcription
– DNA to mRNA
14
Q
Endoplasmic reticulum
A
- Rough
– Studded with ribosomes
15
Q
Ribosomes
A
- Site of translation
– mRNA to protein
16
Q
Golgi apparatus
A
– Takes proteins from ER
– Post-translational modification
• Activates proteins
– Works with vesicles to package p
17
Q
Phospholipids
A
• Phosphate head (-)
– Hydrophilic
• Lipid (long fatty acid chains) tail (neutral)
– Hydrophobic
18
Q
Cholesterol
A
• Between phospholipids
• Fluidity/flexibility
• Reduce permeability
19
Q
Membrane protein receptors
A
• Bind specific ligands
• Cause intercellular response
• Open/close channel
• Promotes endocytosis
20
Q
Examples of chemical messengers
A
- paramones
- hormones
- neurotransmitters
21
Q
Paramones
A
Local (interstitial space)
• Histamines, cytokines, growth factors
22
Q
Hormones
A
• Systemic (bloodstream)
• Multiple target tissues
• Insulin, FSH, GH
23
Q
Neurotransmitters
A
• Neuronal cells after synapse
24
Q
Examples of passive transport
A
- Facilitated diffusion
- Simple diffusion
- Osmotic diffusion
25
Simple diffusion
- O2, CO2
– Move down concentration gradient
26
Facilitated diffusion
-Permitted movement down gradient
– Ions, AA, CHO
27
Active transport
– Independent of gradient
• Na+/K+ ATPase Pump
• Requires energy
– leak, ion gated, ligand gated
28
Chemical gradient
One molecule occurs at higher
concentration on one side of the
membrane
29
Electrical gradient
Charged molecule occurs a higher
concentration on one side of
membrane
30
Electrochemical gradients
Chemical and
electrical gradients exist at the same
time
31
Membrane potential
– Difference in electrical voltage in ECF and ICF
OR
– Separation of charges across membrane
• Na+, K+ Cl-, intracellular proteins –
• harness potential energy
32
Polarity of membrane
- Negative on inside
- positive on outside
33
Only _____ cells respond to changes in potential
Excitable
34
Resting potential is established by
- sodium- potassium pump
- 3 Na out, 2 K in
35
Electrochemical gradient
– + outside
– - inside
36
Na+ concentration gradient
Pumped out, stays out
37
K+ concentration gradient
– Pumped in, flows out
– Equilibrates with electrical gradient
~ -70 to -90 mV
38
For resting potential:
Electrochemical gradient flows ___, Na concentration gradient flows ____, and K concentration gradient flows _____
Outside in, outside in, inside out
39
Membrane potential steps
1. Stimulus
2. Depolarization
3. Repolarization
4.Refractory period
40
Stimulus (membrane potential)
Potential rises above threshold (from -90 to -55 mV)
41
Depolarization
• Voltage-gated Na channel open, Na rushes in (down conc. Gradient)
• Charges reversed (+30mV)
• Adjacent Na channels open
42
Repolarization
• Na channels lock
• Voltage-gated K channels open, K rushes out
• Charges reversed again
43
Refractory period
• K channels close & lock
• No more action potential
• Na/K ATPase restores resting potential
44
Action potential in endocrine cells
• Excretion of pre-packed vesicles (exocytosis)
– Hormones, enzymes
45
Action potential in muscle cells
• Opens Ca channels on membrane/sarcoplasmic reticulum
– Muscle contracts
46
Action potential in neuronal cells
• Secretion of neurotransmitters
– Norepinephrine
– Acetylcholine
47
Cell body of neuronal cells
Soma, nucleus and organelles
48
Dendrites
Somal branches
Receives upstream signals
49
Axon
• Tubular extension/tail
• Transmits signal downstream
• Starts at axon hillock (base of tail)
• Travels to axon terminal (tip of tail)
• Causes neurotransmitter release
50
Myelin coat/sheath
Intermittent lipid cover
51
Axons are formed by _____
Non-neuronal support cells
52
Schwann cells are found in
Peripheral nerves
53
Oligodendrocytes are found in the
Central nervous system
54
Nodes of Ranvier
Bare axon surface where action potential is generated/propagated
55
Saltatory conduction
Action potential skips over myelinated areas
– Increases propagation speed by reducing “stops”
– Requires less Na and K movement
• Less ATP needed to restore concentration gradients with Na/K Pump
56
Synapse
Point where information is passed
57
Synapse is the association between ___ and _____
Axon terminal and target (excitatory) cells
58
Synaptic cleft
Space between knob and target cell
59
Synaptic knob
• Bell-shaped ending of axon
• Contains synaptic vesicles
60
Synaptic vesicles in chemical transmission
Packaged neurotransmitters
61
In chemical transmission ____ causes ____ to open, causing _____
Action potential, Ca channels, exocytosis
62
During chemical transmission ____ move across the cleft causing receptors to bind to ______
Neurotransmitters, target cell
63
Action potentials move from
Pre synaptic to post synaptic cells
64
Role of glial cells
• Structure
• Protection
• Nourishment
65
Astrocytes
– In CNS
– Help organize neurons
– Deliver nutrients, clear neurotransmitters, balance ions
66
Oligodendrocytes
– Myelinate axons in CNS
67
Schwann cells
– Myelination axons in PNS
68
Ependymal cells
– Line brain ventricles/central canal
– Produce cerebrospinal fluid (CSF)
• Surface cilia circulate CSF
69
Microglia
-Phagocytic cells
• Remove invading organisms
70
Neurons make up ___ of total cells in the brain
10%
71
Spinal cord
– Passageway between brain and body
– Coordination of some basic reflexes
– Source of motor nerves
– Destination of sensory nerves
72
Meninges
CNS wrapping membranes
73
Dura mater
– Tough, outmost layer
– Has sinuses where blood and CSF recombine
74
Arachnoid mater
– CSF-filled middle layer
– Villi project into dura sinuses for CSF transfer
75
Pia mater
– High vascular inner layer
– Includes cells that form CSF
76
Brain capillaries have ____ junctions
Tight
77
Molecules that can pass through brain capillaries
• Lipid-soluble particles
-O2, CO2, steroids, alcohol
• Membrane-bound protein carriers
-HIGHLY selective
-Glucose, AAs, ions
78
Cerebral spinal fluid
Cushions brain (and spinal cord) & provides nutrients
79
Cerebrum
– Largest area of the brain
– Highest complexity
– Highest thought
• Consciousness
• High degree of educability
80
Cerebral cortex
Outermost tissue
81
Gray matter
• Cell bodies/dendrites
• Vasculature
82
White matter
• Bundles of myelinated axon fibers
• “tracks” for neural pathways
83
Occipital lobe
Visual processing cortex
84
Temporal lobe
Auditory cortex
85
Parietal lobe
• Somatosensory cortex
• Body position
86
Primary motor cortex
Initiate movement
87
Supplementary motor complex
Coordinating movement
88
Premotor complex
Planning movement/problem solving
89
Broca’s area
Frontal lobe
• Articulation/execution of speech
• Based on information from Wernicke’s area
90
Wernicke’s area
Temporal lobe
• Articulation/execution of speech
• Based on information from Wernicke’s area
91
Hippocampus
• Learning and memory
92
Olfactory bulb
Smell
93
Basal nuclei
Motor control and executive functions
94
Vestibulocerebellum
• Maintains balance
• Controls eye movement
95
Spinocerebellum
• Coordinates w/ cerebral cortex for motor control
• Predicts body position
96
Cerebrocerebellum
• Majority of cerebellum
• Lower voluntary action
• Some procedural memories
97
Brain stem
• “lowest”/least complex function
– Sleep/wake, alertness, basic touch/pressure
– Systems activity
98
Medulla
– Swallowing, salivation
– Vomiting (CTZ)
– Respiration
– Blood pressure
– Heart rate
99
Pons
– Changes in RR and BP
– Analgesic system, sleep
100
Midbrain
Motivation
101
Spinal cord contains
– White & gray matter
– Meninges
– CSF
102
Spinal withdrawal
Withdrawing body part from damaging sources
103
Spinal stretch
Contracting skeletal muscle to counteract stretch
104
Crossed extensor reflex
Shifts load from injured limb to other
105
sensory nerves
afferent division
-detect conditions in body tissues
-alert CNS
106
motor nerves
efferent division
-begins in CNS
-terminate in target tissues (excitable cells)
107
somatic division
voluntary
108
autonomic division
involuntary
109
sensory nerves (3)
-receptor/dendrite
-axon
-cell body
110
receptor/dendrite
-Receptor near dendrite tips
-Receptor part of dendrite tips
-Affect axon hillock potential
111
axon
-Connects to dendrites
-Carries signal to CNS (via action potential)
112
cell body
-Axon “offshoot”
-Skips depolarization during action potential
-Groups located in dorsal root ganglia
113
Sensory nerve receptor types
-Photoreceptors: light
-Mechanoreceptors: stretch/bending
-Thermoreceptors: heat/cold
-Osmoreceptors: ECF molarity
-Chemoreceptors: detect chemicals
-Taste/smell
-O2/CO2 in blood
-Nutrients in GI tract
-Nociceptors: pain
114
the intensity of sensation in nerve receptors is determined by _______
action potential amount
115
frequency code
1 neuron stimulating another over and over
116
population code
several neurons stimulating an action/working against one another
117
tonic receptors
gradual adaptation (ex. Muscle stretch receptors)
118
phasic receptors
rapidly adapt (ex. Odor, touch, temperature)
119
ANS efferent motor division: voluntary
Short preganglionic neurons originate in _________
and their correlating neurotransmitter is _______
middle of the spinal cord
acetylcholine (ACh)
120
ANS efferent motor division: voluntary
Long preganglionic neurons originate from ________
and their correlating neurotransmitter is _______
ganglion to target
norepinephrine (NE)
121
ANS efferent motor division: involuntary
Short preganglionic neurons originate in _________
and their correlating neurotransmitter is _______
ganglion to target
acetylcholine (ACh)
122
ANS efferent motor division: voluntary
Long preganglionic neurons originate in _________
and their correlating neurotransmitter is _______
brain stem or low spinal cord
acetylcholine (ACh)
123
Somatic nervous system (SNS)
-motor neurons
-one-neuron "chain"
-originate at ventral horn of spinal cord
-axon is continuous to skeletal muscle
124
SNS stimulates the ______ ONLY
skeletal muscle
