Exam 1 Flashcards
(220 cards)
1
Q
What model describes the structure of the cell membrane?
A
The Fluid Mosaic Model.
2
Q
What limits diffusion across cell membranes?
A
The hydrophobic interior of the lipid bilayer.
3
Q
What are some examples of nonpolar molecules that diffuse rapidly through lipid membranes?
A
Oxygen, carbon dioxide, fatty acids, and steroid hormones.
4
Q
What type of molecules do not readily diffuse through membranes?
A
Polar molecules and hydrophilic substances.
5
Q
Define diffusion.
A
The movement of molecules from one location to another due to random thermal motion.
6
Q
How does diffusion time relate to distance?
A
Diffusion time increases proportionally to the square of the distance.
7
Q
What are non-penetrating solutes?
A
Solutes that cannot cross the membrane unassisted.
8
Q
What is an isotonic solution?
A
A solution with the same concentration of non-penetrating solutes as normal extracellular fluid.
9
Q
What is a hypotonic solution?
A
A solution with a lower concentration of non-penetrating solutes compared to normal extracellular fluid.
10
Q
What is a hypertonic solution?
A
A solution with a higher concentration of non-penetrating solutes compared to normal extracellular fluid.
11
Q
What is osmolarity based on?
A
Units that take into account dissociation, unlike molarity.
12
Q
How do ion channels facilitate diffusion?
A
By allowing specific ions like Na+, K+, Cl–, and Ca2+ to pass through the membrane.
13
Q
What are the characteristics of ion channels?
A
They can be unregulated or gated (ligand, voltage, or mechanically gated).
14
Q
What is the key difference between ion channels and transporters?
A
Transporters require binding and conformational changes, while ion channels do not.
15
Q
What is facilitated diffusion?
A
The passive transport of molecules across a membrane via transport proteins.
16
Q
What does saturation mean in facilitated diffusion?
A
There is a maximum flux of molecules that can be achieved.
17
Q
What is active transport?
A
The movement of molecules against the concentration gradient using energy.
18
Q
Name two types of active transport.
A
Primary (using ATP) and secondary (using an electrochemical gradient).
19
Q
What is homeostasis?
A
The dynamic process of maintaining physiological variables within a normal range.
20
Q
What is dynamic constancy?
A
A state where physiological variables change short-term but remain stable long-term.
21
Q
What model describes the structure of the cell membrane?
A
The Fluid Mosaic Model.
22
Q
What limits diffusion across cell membranes?
A
The hydrophobic interior of the lipid bilayer.
23
Q
What are some examples of nonpolar molecules that diffuse rapidly through lipid membranes?
A
Oxygen, carbon dioxide, fatty acids, and steroid hormones.
24
Q
What type of molecules do not readily diffuse through membranes?
A
Polar molecules and hydrophilic substances.
25
Define diffusion.
The movement of molecules from one location to another due to random thermal motion.
26
How does diffusion time relate to distance?
Diffusion time increases proportionally to the square of the distance.
27
What are non-penetrating solutes?
Solutes that cannot cross the membrane unassisted.
28
What is an isotonic solution?
A solution with the same concentration of non-penetrating solutes as normal extracellular fluid.
29
What is a hypotonic solution?
A solution with a lower concentration of non-penetrating solutes compared to normal extracellular fluid.
30
What is a hypertonic solution?
A solution with a higher concentration of non-penetrating solutes compared to normal extracellular fluid.
31
What is osmolarity based on?
Units that take into account dissociation, unlike molarity.
32
How do ion channels facilitate diffusion?
By allowing specific ions like Na+, K+, Cl–, and Ca2+ to pass through the membrane.
33
What are the characteristics of ion channels?
They can be unregulated or gated (ligand, voltage, or mechanically gated).
34
What is the key difference between ion channels and transporters?
Transporters require binding and conformational changes, while ion channels do not.
35
What is facilitated diffusion?
The passive transport of molecules across a membrane via transport proteins.
36
What does saturation mean in facilitated diffusion?
There is a maximum flux of molecules that can be achieved.
37
What is active transport?
The movement of molecules against the concentration gradient using energy.
38
Name two types of active transport.
Primary (using ATP) and secondary (using an electrochemical gradient).
39
What is homeostasis?
The dynamic process of maintaining physiological variables within a normal range.
40
What is dynamic constancy?
A state where physiological variables change short-term but remain stable long-term.
41
What is the role of feedback loops in physiology?
They control physiological processes to maintain homeostasis.
42
What does a positive feedback loop do?
Enhances the production of the product.
43
What does a negative feedback loop do?
Stops the process once the set point has been reached.
44
What are afferent pathways responsible for in homeostasis?
Carrying signals toward the control center.
45
What are efferent pathways responsible for in homeostasis?
Carrying signals away from the control center.
46
What is the main function of membranes?
To regulate the movement of molecules between the inside and outside of cells.
47
What is signal amplification in cell signaling?
Increasing the magnitude of the cell's response to a stimulus.
48
What are second messengers?
Intracellular signaling molecules released in response to extracellular signals.
49
What is a ligand?
A molecule that binds to a specific receptor.
50
What is the lock-and-key model in cellular signaling?
The concept that ligands and receptors must fit together precisely to initiate a response.
51
What is the role of kinases in cell signaling?
To phosphorylate proteins and alter their function.
52
What is the significance of DAG/IP3 in signaling?
They act as secondary messengers to regulate cellular processes.
53
How does cAMP function as a second messenger?
By activating protein kinases, leading to signal amplification.
54
What is the role of ion pumps in active transport?
To move ions against their concentration gradient using energy.
55
How does Na+/K+ ATPase maintain cell potential?
By actively transporting Na+ out and K+ into the cell.
56
What is the difference between primary and secondary active transport?
Primary uses ATP directly, while secondary uses an existing gradient.
57
What is the primary function of membrane transport proteins?
To move substances across cell membranes.
58
How do voltage-gated channels operate?
They open or close in response to changes in membrane potential.
59
What is the role of mechanically gated ion channels?
To open in response to physical deformation of the membrane.
60
What determines the specificity of ion channels?
Pore size, charge, and binding sites.
61
What is mediated transport?
The movement of molecules via specific transport proteins.
62
What limits the rate of mediated transport?
The saturation of the transport protein.
63
What is the difference between passive and active transport?
Passive transport does not require energy, while active transport does.
64
What is the main purpose of cellular signaling?
To transmit information from the extracellular environment to the cell interior.
65
What is homeostatic regulation?
The adjustment of physiological systems to maintain stability.
66
What is the primary role of receptors in cell signaling?
To detect signaling molecules and initiate a response.
67
What are the two types of feedback mechanisms?
Positive and negative feedback.
68
What is the significance of intracellular fluid (ICF)?
It contains the majority of the cell's water content.
69
What is extracellular fluid (ECF)?
Fluid outside cells, including interstitial fluid and plasma.
70
Why is membrane permeability important?
It determines how substances enter or leave a cell.
71
What is the role of the Na+/K+ pump in cells?
To maintain the electrochemical gradient by moving Na+ out and K+ in.
72
What are the key components of a reflex arc?
Receptor, afferent pathway, integrating center, efferent pathway, and effector.
73
What is chemical specificity in receptor-ligand binding?
The ability of a receptor to bind only specific ligands.
74
What is affinity in ligand-receptor interactions?
The strength of the binding between ligand and receptor.
75
Why is signal transduction important?
It converts an extracellular signal into a functional intracellular response.
76
What happens in signal amplification?
A single signaling molecule triggers a cascade, producing multiple intracellular signals.
77
What is the primary function of second messengers?
To relay signals from receptors to target molecules inside the cell.
78
How do lipophilic signals typically enter cells?
By diffusing through the lipid bilayer.
79
What are membrane-bound receptors?
Receptors located on the cell surface that bind extracellular ligands.
80
What is the overall goal of homeostasis?
To maintain a stable internal environment despite external changes.
81
What are the general functions of the endocrine system?
Maintaining homeostasis, controlling reproduction, regulating growth and metabolism, and controlling digestion.
82
What role does the endocrine system play in blood composition?
Regulates the amount of substances dissolved in blood, such as glucose, cations, and anions.
83
How does the endocrine system control reproductive activities?
It affects development, function, and expression of sexual behaviors.
84
What are endocrine reflexes?
Preprogrammed responses to certain stimuli that regulate hormone secretion.
85
What are the three types of stimulation that initiate endocrine reflexes?
Hormonal, humoral, and nervous stimulation.
86
What is hormonal stimulation?
Hormone release in response to another hormone, e.g., TSH stimulates thyroid hormone release.
87
What is humoral stimulation?
Hormone release triggered by changes in blood levels of certain ions or nutrients.
88
What is nervous stimulation in the endocrine system?
Hormone release triggered by nervous system signals, e.g., epinephrine release during stress.
89
What are the primary endocrine organs?
Pituitary, pineal, thyroid, parathyroid, and adrenal glands.
90
How do local hormones differ from circulating hormones?
Local hormones do not circulate in the blood and act on neighboring cells or the same cell that secretes them.
91
What is autocrine stimulation?
When a local hormone initiates changes in the same cell that produced it.
92
What is paracrine stimulation?
When a local hormone initiates changes in neighboring cells of a different type.
93
What is the difference between endocrine and nervous system signaling?
Endocrine signaling uses hormones in the blood and has longer-lasting, widespread effects.
94
What is the half-life of a hormone?
The time it takes for the hormone concentration to decrease by half.
95
How do water-soluble hormones travel in the blood?
They dissolve easily in the blood and do not require carrier proteins.
96
How do lipid-soluble hormones travel in the blood?
They require carrier proteins to be transported through the bloodstream.
97
What is the primary function of the hypothalamus?
To regulate the release of hormones from the pituitary gland.
98
What hormones are released by the posterior pituitary?
Oxytocin and antidiuretic hormone (ADH).
99
What is the role of oxytocin?
Stimulates milk ejection and promotes emotional bonding.
100
What is the role of ADH?
Regulates water balance and osmolarity in the body.
101
What are the functions of the anterior pituitary hormones?
They regulate growth, metabolism, reproduction, and stress response.
102
What hormone is involved in milk production and lactation?
Prolactin.
103
What is the role of growth hormone (GH)?
Stimulates growth and cell reproduction.
104
What triggers cortisol release from the adrenal cortex?
Adrenocorticotropic hormone (ACTH) from the anterior pituitary.
105
What is the adrenal medulla responsible for secreting?
Epinephrine and norepinephrine during stress.
106
What are the main functions of cortisol?
Maintaining glucose levels, reducing inflammation, and responding to stress.
107
What is Cushing's syndrome?
Excess cortisol leading to muscle weakness, hyperglycemia, and hypertension.
108
What is adrenal insufficiency?
A condition where the adrenal glands do not produce enough cortisol.
109
What are the effects of hyperthyroidism?
Increased metabolism, heat intolerance, and weight loss.
110
What are the effects of hypothyroidism?
Decreased metabolism, fatigue, and weight gain.
111
What causes goiter in hypothyroidism?
Excessive TSH stimulation due to low thyroid hormone levels.
112
What hormone is critical for regulating calcium levels?
Parathyroid hormone (PTH).
113
What is the primary function of insulin?
To lower blood glucose by promoting its uptake into cells.
114
What hormone antagonizes insulin's effects?
Glucagon.
115
What is the primary effect of glucagon?
Increases blood glucose by stimulating glycogen breakdown.
116
What are the hormones involved in the stress response?
Cortisol, epinephrine, and norepinephrine.
117
What role do gonadotropins (LH and FSH) play?
They regulate the function of the gonads and the production of sex hormones.
118
What is the main function of testosterone in males?
Promotes sperm production and secondary sexual characteristics.
119
What is estrogen responsible for in females?
Regulating the menstrual cycle and maintaining secondary sexual characteristics.
120
What is the function of progesterone?
Prepares the uterus for pregnancy and maintains it during early stages.
121
What hormone regulates the ovarian cycle?
Luteinizing hormone (LH).
122
What hormone increases during labor to stimulate contractions?
Oxytocin.
123
What does the thyroid gland primarily produce?
Thyroxine (T4) and triiodothyronine (T3).
124
What is the primary function of calcitonin?
Lowers blood calcium levels by inhibiting osteoclast activity.
125
What is the role of aldosterone?
Regulates sodium and potassium balance by promoting sodium retention.
126
127
What is the primary function of the nervous system?
To serve as the body's primary communication and control system.
128
What specialized structures collect information in the nervous system?
Receptors that monitor changes in the environment.
129
What is the main role of dendrites in a neuron?
To receive signals from other neurons.
130
What is the function of the cell body in a neuron?
Processing signals and cell metabolism.
131
What is the role of the axon in a neuron?
To transmit electrical impulses away from the cell body.
132
What are the three functional classes of neurons?
Afferent neurons, interneurons, and efferent neurons.
133
What is the role of afferent neurons?
To transmit information to the CNS from peripheral receptors.
134
What is the primary function of interneurons?
To integrate signals and form reflex circuits.
135
What is the function of efferent neurons?
To transmit signals from the CNS to effector cells.
136
What are glial cells?
Supportive cells that are the most numerous in the CNS.
137
What is myelination?
The process of wrapping an axon with a myelin sheath to insulate it.
138
What is the role of neurolemmocytes in the PNS?
To myelinate a single axon segment.
139
What is the function of oligodendrocytes in the CNS?
To myelinate multiple axons with their extensions.
140
What is the Blood-Brain Barrier (BBB)?
A selective barrier that protects the brain by controlling substance entry.
141
What ions are most involved in the resting membrane potential?
K+, Na+, Cl-, and proteins with negative charges.
142
What is depolarization?
A decrease in membrane potential making the inside of the cell less negative.
143
What is repolarization?
The return of the membrane potential to resting value after depolarization.
144
What is hyperpolarization?
An increase in membrane potential making the inside more negative.
145
What is a graded potential?
A small, localized change in membrane potential that varies in size.
146
What is an action potential?
A rapid, large change in membrane potential that propagates along an axon.
147
Q: What is the threshold potential for generating an action potential?
A: Approximately -55 mV.
148
Q: What is saltatory conduction?
A: Rapid transmission of action potentials in myelinated axons jumping between nodes of Ranvier.
149
Q: What is continuous conduction?
A: Slow transmission of action potentials in unmyelinated axons.
150
Q: What is an excitatory postsynaptic potential (EPSP)?
A: Depolarization that brings the membrane potential closer to threshold.
151
Q: What is an inhibitory postsynaptic potential (IPSP)?
A: Hyperpolarization that moves the membrane potential away from threshold.
152
Q: What is temporal summation?
A: Multiple signals from the same neuron add together over time.
153
Q: What is spatial summation?
A: Signals from multiple neurons combine at the postsynaptic membrane.
154
Q: What is the function of SNARE proteins?
A: Facilitate vesicle fusion for neurotransmitter release.
155
Q: What role do voltage-gated calcium channels play at the synapse?
A: Trigger neurotransmitter release upon depolarization.
156
Q: What are the two types of synapses?
A: Chemical and electrical.
157
Q: What characterizes an electrical synapse?
A: Direct transmission of impulses via gap junctions.
158
Q: What characterizes a chemical synapse?
A: Neurotransmitter release into the synaptic cleft.
159
Q: What neurotransmitter is primarily excitatory in the CNS?
A: Glutamate.
160
Q: What neurotransmitter is primarily inhibitory in the CNS?
A: GABA.
161
Q: What is synaptic plasticity?
A: The ability of synapses to strengthen or weaken over time.
162
Q: What is long-term potentiation (LTP)?
A: A long-lasting increase in synaptic strength.
163
Q: What is the role of acetylcholine at the neuromuscular junction?
A: Stimulates muscle contraction.
164
Q: What are the two types of acetylcholine receptors?
A: Nicotinic and muscarinic.
165
Q: What enzyme breaks down acetylcholine?
A: Acetylcholinesterase.
166
Q: What is the refractory period?
A: The time during which a neuron cannot fire another action potential.
167
Q: What is the difference between absolute and relative refractory periods?
A: Absolute: no AP possible; Relative: AP possible with strong stimulus.
168
Q: What is Multiple Sclerosis (MS)?
A: An autoimmune disorder where myelin is damaged.
169
Q: What is the effect of myelin loss in MS?
A: Slower action potential propagation.
170
Q: What is synaptic fatigue?
A: Decreased neurotransmitter release due to prolonged activity.
171
Q: What is an action potential propagation?A: Movement of the action potential along the axon.
172
Q: What is hyperkalemia?
A: Excessive potassium in the blood affecting nerve function.
173
Q: What is a seizure?
A: Uncontrolled electrical activity in the brain.
174
Q: What is epilepsy?
A: Chronic condition characterized by recurrent seizures.
175
Q: What is neuroplasticity?
A: The nervous system's ability to adapt and reorganize.
176
Q: What is a neurotransmitter?
A: A chemical messenger between neurons.
177
Q: What is dopamine associated with?
A: Reward and pleasure
178
Q: What is serotonin's primary role?
A: Regulating mood and appetite
179
Q: What is Parkinson's disease?
A: Degeneration of dopamine-producing neurons.
180
Q: What is the role of the sodium-potassium pump?
A: Maintains resting membrane potential by moving Na+ out and K+ in.
181
Q: What is synaptic pruning?
A: Elimination of weak or unused synapses.
182
Q: What is synaptic integration?
A: Summing of EPSPs and IPSPs to determine action potential firing.
183
Q: What is a nerve impulse?
A: An electrical signal traveling along a neuron.
184
Q: What is a motor neuron?
A: A neuron that transmits signals to muscles.
185
Q: What is neurogenesis?
A: Formation of new neurons.
186
Q: What neurotransmitter is released at parasympathetic synapses?
A: Acetylcholine (ACh) at both pre- and postganglionic synapses.
187
Q: What neurotransmitter is released at sympathetic preganglionic synapses?
A: Acetylcholine (ACh).
188
Q: What is the primary function of the sympathetic division?
A: Activates the "fight or flight" response.
189
Q: What are adrenergic receptors classified as?
A: Alpha (α) and beta (β) receptors.
190
Q: What is the effect of the parasympathetic system on the pupils?
A: Constriction of pupils.
191
Q: What are the main cranial nerves involved in parasympathetic control?
A: Cranial nerves III, VII, IX, and X.
192
Q: How does the sympathetic system affect the pupils?
A: Dilates the pupils.
193
Q: What is autonomic dysreflexia?
A: Exaggerated autonomic response, often due to spinal cord injury.
194
Q: What type of receptor is muscarinic?
A: G-protein-coupled receptor (GPCR).
195
Q: What role does the brainstem play in the ANS?
A: Houses major autonomic reflex centers.
196
Q: How does the sympathetic system affect the heart?
A: Increases heart rate and force of contraction.
197
Q: How does the sympathetic system prepare the body for exercise?
A: Increases heart rate, dilates airways, and releases glucose.
198
Q: What does the autonomic nervous system (ANS) regulate?
A: Involuntary actions, maintaining homeostasis, and regulating organ activity.
199
Q: What is dual innervation?
A: Most organs receive input from both sympathetic and parasympathetic divisions.
200
Q: What are cholinergic neurons?
A: Neurons that release acetylcholine (ACh).
201
Q: What are adrenergic neurons?
A: Neurons that release norepinephrine (NE).
202
Q: What are the two types of cholinergic receptors?
A: Nicotinic and muscarinic receptors.
203
Q: What neurotransmitter is released at sympathetic postganglionic synapses?
A: Norepinephrine (NE).
204
Q: Where are nicotinic receptors found?
A: On all ganglionic neurons and the adrenal medulla.
205
Q: What is the primary function of the parasympathetic division?
A: Promotes "rest and digest" activities.
206
Q: How does the parasympathetic system affect the bladder?
A: Promotes contraction and urination.
207
Q: How does the hypothalamus influence the ANS?
A: Regulates autonomic responses based on internal and emotional states.
208
Q: What is the main function of the adrenal medulla in the sympathetic response?
A: Secretes epinephrine and norepinephrine into the bloodstream.
209
Q: What is mass activation in the sympathetic system?
A: Simultaneous activation of multiple organs during stress.
210
Q: What effect does ACh binding to muscarinic receptors on the heart have?
A: Slows the heart rate.
211
Q: What is the role of beta-2 receptors?
A: Smooth muscle relaxation, such as bronchodilation.
212
Q: What is the difference between somatic and autonomic nervous systems?
A: Somatic controls voluntary muscles; autonomic regulates involuntary functions.
213
Q: How does the parasympathetic system affect digestion?
A: Stimulates digestive processes and increases motility.
214
Q: What triggers autonomic dysreflexia?
A: Stimuli such as bladder distension or skin irritation.
215
Q: What are the two main divisions of the ANS?
A: Sympathetic and parasympathetic divisions.
216
Q: What is a local response in the parasympathetic system?
A: Targeted activation of specific organs.
217
Q: What is autonomic tone?
A: The balance between sympathetic and parasympathetic activity.
218
Q: How do beta-blockers work?
A: They inhibit beta receptors, reducing heart rate and blood pressure.
219
Q: What is the effect of norepinephrine binding to alpha-1 receptors?
A: Vasoconstriction and increased blood pressure.
220
Q: What happens to blood vessels during sympathetic activation?
A: Vasoconstriction and increased blood pressure.
