Physiology Flashcards
(572 cards)
1
Q
What is the Central Nervous System (CNS) composed of?
A
Brain + Spinal Cord
2
Q
When does the Central Nervous System develop?
A
3rd week of embryogenesis (neurulation) from the ectoderm layer
3
Q
What connects the spinal cord to the brain?
A
Foramen magnum
4
Q
What does the Peripheral Nervous System (PNS) consist of?
A
12 cranial nerves (CNs) + 31 pairs of spinal nerves
5
Q
What type of neurons have no dendrites and only an axon branch?
A
Unipolar neurons
6
Q
What are the four types of neurons?
A
- Unipolar
- Bipolar
- Multipolar
- Pseudo-unipolar
7
Q
What is the role of astrocytes in the CNS?
A
Blood-brain barrier (BBB) formation
8
Q
What do oligodendrocytes produce in the CNS?
A
Myelin sheath
9
Q
What is the function of microglia?
A
CNS macrophages
10
Q
What lines the ventricles and circulates cerebrospinal fluid (CSF)?
A
Ependyma
11
Q
What is the role of the cytoskeleton in neurons?
A
Crucial for neurotransmitter release and transport, cell shape, and motility
12
Q
What is the function of the dura mater?
A
Outermost fibrous, loose coat of meninges
13
Q
What is the function of cerebrospinal fluid (CSF)?
A
- Shock absorption
- Nutrient provision
- Waste removal
- Homeostasis
14
Q
What is the primary vascular supply for the brain?
A
Internal carotid arteries
15
Q
What type of stroke is caused by blockage of blood flow?
A
Ischemic Stroke
16
Q
What does the medulla oblongata control?
A
Autonomic functions (e.g., respiration, heart rate, digestion)
17
Q
What is the role of the thalamus?
A
Processes sensory and motor signals to the cerebral cortex
18
Q
What are the four lobes of the cerebral hemispheres?
A
- Frontal Lobe
- Temporal Lobe
- Parietal Lobe
- Occipital Lobe
19
Q
What is the function of the pancreas?
A
Secretes insulin (lowers blood glucose) and glucagon (raises blood glucose)
20
Q
What is the primary function of peptide hormones?
A
Bind to receptors on the cell surface, triggering rapid responses
21
Q
What type of hormone is estrogen?
A
Steroid hormone
22
Q
What is the structure of amino-acid derived hormones?
A
Derived from tyrosine and iodine
23
Q
What is the primary role of the hypothalamus?
A
Controls the pituitary via releasing hormones
24
Q
What does the thyroid gland regulate?
A
Metabolism
25
What is the active form of thyroid hormone?
T3 (triiodothyronine)
26
What are the two types of adrenal hormones produced by the adrenal glands?
* Adrenaline
* Noradrenaline
27
What is the role of the gonads?
Produce sex hormones (testosterone in males, estrogen and progesterone in females)
28
What is the primary function of the pleura?
Cushioning and facilitating smooth lung movement
29
What is the function of surfactant in the alveoli?
Reduces surface tension, prevents collapse
30
What does Fick’s Law state about gas diffusion?
Depends on surface area, membrane thickness, pressure difference
31
What is the function of chemotactic receptors in the respiratory system?
Detect O2 and CO2 levels
32
What is the primary mechanism of inhalation?
Active process, diaphragm and intercostal muscles contract
33
What is the primary role of the ventral respiratory group?
Controls forced expiration
34
What is the primary effect of hyperthyroidism?
Speeds up metabolic processes (e.g., weight loss, heat intolerance)
35
What is the purpose of negative feedback loops in hormone regulation?
Ensure homeostasis
36
What are the two types of bronchial dysfunction?
* Bronchoconstriction
* Bronchodilation
37
What is the role of the SA Node in the heart?
Pacemaker; fires first due to highest excitability
38
What primarily influences heart rate?
Parasympathetic activation (vagus nerve, ACh)
39
What factors influence stroke volume (SV)?
* Preload (EDV)
* Afterload (Resistance)
40
What is the primary difference between right and left ventricles?
* Right Ventricle: Pumps blood to lungs, low pressure
* Left Ventricle: Pumps blood to body, high pressure
41
What is the function of the Right Ventricle?
Pumps blood to lungs
42
What is the function of the Left Ventricle?
Pumps blood to body
43
What is the wall thickness of the Right Ventricle?
Thin
44
What is the wall thickness of the Left Ventricle?
Thick
45
What shape is the Right Ventricle?
Crescent
46
What shape is the Left Ventricle?
Circular
47
What type of pressure does the Right Ventricle exert?
Low
48
What type of pressure does the Left Ventricle exert?
High
49
What is the resistance in the Right Ventricle?
Low
50
What is the resistance in the Left Ventricle?
Variable
51
What is the flow rate in the Right Ventricle?
High
52
What is the flow rate in the Left Ventricle?
Variable
53
What is the role of the SA Node?
Pacemaker; fires first due to highest excitability
54
What initiates an Action Potential (AP)?
Na⁺ entry → Depolarization (not Ca²⁺ triggered)
55
What resets the cycle of Action Potential?
Hyperpolarization
56
What always precedes a heartbeat?
AP
57
What does the Frank-Starling Law state?
More blood in (↑ EDV) → More stretch → Stronger contraction
58
How does Total Peripheral Resistance (TPR) relate to cardiac function?
↑ TPR → More resistance → Harder to pump blood back
59
What factors regulate blood return to the heart?
* Sympathetic activity
* Skeletal muscles
* Ventilation
60
What regulates venous return?
* Sympathetic activation (venoconstriction)
* Skeletal muscle contractions (muscle pump)
* Respiratory movements (thoracic pump)
61
What is the purpose of the Renin-Angiotensin-Aldosterone (RAA) System?
Regulates BP & fluid balance
62
What happens when blood pressure decreases in the RAA system?
Kidneys release renin
63
What does renin convert angiotensinogen into?
Angiotensin I
64
What converts angiotensin I into angiotensin II?
ACE
65
What are the effects of angiotensin II?
* Vasoconstriction → ↑ BP
* Aldosterone release → Na⁺ & water retention (↑ blood volume)
66
What is the main function of the urinary tract?
Filters blood and excretes metabolic products
67
What regulates pH in the body?
Acid-base balance
68
What occurs during acidosis?
Bradycardia & hyperventilation
69
What is the primary organ involved in hematopoiesis?
Kidneys
70
What is the weight of each kidney?
~150g
71
What functions do kidneys perform?
* Regulate blood volume & pressure
* Water & ion excretion
* Electrolyte management
* Plasma pH control
* Nutrient absorption
* Red blood cell biosynthesis
* Bone health
* Excretion of metabolic & foreign toxins
72
What are the main components of the nephron pathway?
* Afferent arteriole
* Glomerulus (Bowman’s capsule)
* Efferent arteriole
* Proximal convoluted tubule
* Descending limb (Loop of Henle)
* Ascending limb (Loop of Henle)
* Collecting duct
73
What is the Net Filtration Pressure formula?
Blood hydrostatic pressure (55 mmHg) - Filtrate hydrostatic pressure (15 mmHg) - Oncotic pressure (30 mmHg) = 10 mmHg
74
What is the normal range for Glomerular Filtration Rate (GFR)?
90-120 mL/min/1.73m^2
75
What is the myogenic response in kidney function?
Increased BP → Afferent artery stretch → Activates Na+ channels → Vasoconstriction
76
What is Tubuloglomerular Feedback?
Increased perfusion → Increased NaCl to Macula Densa → ATP release → Converted to adenosine → A1 receptor activation → Ca2+ release → Vasoconstriction of afferent arteriole
77
What does Atrial Natriuretic Peptide (ANP) do?
Released in response to increased blood volume; promotes Na+ & water excretion
78
What are the components of the urinary system?
* Ureters
* Bladder
* Urethra
79
What is the first step in urine formation?
Glomerular Filtration
80
What is tubular reabsorption?
Na+ Reabsorption, Water Reabsorption, Nutrient & Ion Reabsorption
81
What is tubular secretion?
Removes protein-bound drugs, metabolites, toxins, & waste products
82
What is the normal specific gravity of urine?
1.005 - 1.03
83
What is the countercurrent multiplier mechanism?
Loop of Henle & collecting duct increase interstitial osmolality
84
What initiates micturition?
Bladder stretch
85
What are the main roles of the liver?
* Metabolic Functions
* Synthetic Functions
* Storage Functions
* Homeostasis
86
What are the phases of drug metabolism?
* Phase I: Oxidation, Reduction, Hydrolysis
* Phase II: Conjugation Reactions
87
What is the main role of albumin in the body?
Maintains oncotic pressure and transports various substances
88
What is the purpose of the complement system?
Enhances antibodies & phagocytes, clears microbes, promotes inflammation
89
What are Pattern Recognition Receptors (PRRs)?
Bind to Pathogen-Associated Molecular Patterns (PAMPs)
90
What types of antigens do MHC I and MHC II present?
* MHC I: Endogenous antigens to CD8+ T-cells
* MHC II: Exogenous antigens to CD4+ T-cells
91
What is the role of T-Cells in the immune response?
Recognize antigenic protein fragments via MHC molecules on APCs
92
What does MHC stand for in humans?
Major Histocompatibility Complex
## Footnote
HLA is the human equivalent of MHC.
93
What type of antigens do MHC I present?
Endogenous antigens to CD8+ T-cells
94
Where is MHC II found?
On Antigen-Presenting Cells (APCs)
95
What role does MHC compatibility play in organ transplants?
Determines acceptance or rejection
96
What are the different types of CD4+ Helper T-Cells?
* Th1: Cell-mediated response
* Th2: Antibody production
* Th17: Neutrophil recruitment
* Treg: Suppress immune response
* Tfh: Facilitate antibody production
97
What is the main function of CD8+ Cytotoxic T-Cells?
Kill infected cells via perforin & granzymes
98
What distinguishes Naïve T-Cells from Effector T-Cells?
Naïve: First antigen exposure; Effector: Activated and ready to kill
99
What is required for T-cell activation?
CTLA-4 (inhibitory, derived from CD28)
100
What is the primary function of B-Cells?
Produce antibodies
101
List the functions of antibodies.
* Neutralization of toxins/pathogens
* Opsonization
* Complement activation
102
What is Class Switch Recombination in B-cells?
Switching antibody isotype based on T-cell cytokine signaling
103
What is the difference between the Primary and Secondary Immune Response?
* Primary: Maximal response within 10 days
* Secondary: Faster (4 days) due to memory cells
104
Define tolerance in the immune system.
Immune system's non-reactivity to self-antigens
105
What are the two types of Tolerance?
* Central Tolerance
* Peripheral Tolerance
106
What mechanisms are involved in Tolerance?
* Deletion (Apoptosis)
* Anergy
* Ignorance
107
What is the role of Treg cells?
Maintain self-tolerance & prevent autoimmunity
108
What is the function of the Autonomic Nervous System (ANS)?
Regulate involuntary bodily functions
109
What are the two divisions of the ANS?
* Sympathetic
* Parasympathetic
110
What is the primary function of the Parasympathetic Nervous System?
Restores homeostasis after stress
111
List effects of the Parasympathetic Nervous System.
* Pupil constriction
* Increased saliva production
* Decreased heart rate
* Bronchoconstriction
* Increased peristalsis & digestion
* Increased bile secretion
* Bladder contraction
112
What is the origin of the Parasympathetic Nervous System?
Brainstem & sacral spinal cord
113
What is the primary function of the Sympathetic Nervous System?
Prepares body for stress, exercise, or danger
114
List effects of the Sympathetic Nervous System.
* Pupil dilation
* Decreased saliva production
* Increased heart rate
* Bronchodilation
* Decreased peristalsis & digestion
* Bladder relaxation
115
What neurotransmitter is released by all preganglionic neurons?
Acetylcholine (Ach)
116
What type of receptors does Acetylcholine bind to?
* Nicotinic receptors
* Muscarinic receptors
117
What receptors do Norepinephrine (NE) and Epinephrine (EPI) bind to?
* Alpha receptors (α1, α2)
* Beta receptors (β1, β2, β3)
118
What is the primary function of α1 receptors?
Vasoconstriction (increases BP), pupil dilation
119
What is the primary function of β2 receptors?
Bronchodilation, vasodilation
120
What is the key difference in fiber length between PNS and SNS?
* PNS: Long preganglionic, short postganglionic
* SNS: Short preganglionic, long postganglionic
121
What happens during PNS dominance?
Maintains baseline homeostasis
122
What can disruptions in ANS lead to?
Disorders such as orthostatic hypotension, autonomic neuropathy
123
Autonomic Nervous System (ANS)
Two divisions: Sympathetic ('fight or flight') & Parasympathetic ('rest & digest')
124
Neurotransmitter: Acetylcholine (Ach)
Universal neurotransmitter, with norepinephrine (NE) for sympathetic post-ganglionic fibers.
125
Parasympathetic Nervous System (PNS)
Function: Restores homeostasis after stress; conserves energy.
126
Pupil constriction
Effect of the Parasympathetic Nervous System.
127
Increased saliva production
Effect of the Parasympathetic Nervous System.
128
Decreased heart rate (HR)
Effect of the Parasympathetic Nervous System.
129
Bronchoconstriction
Effect of the Parasympathetic Nervous System.
130
Increased peristalsis & digestion
Effect of the Parasympathetic Nervous System.
131
Increased bile secretion
Effect of the Parasympathetic Nervous System.
132
Bladder contraction
Promotes urination; effect of the Parasympathetic Nervous System.
133
Sympathetic Nervous System (SNS)
Function: Prepares body for stress, exercise, or danger.
134
Pupil dilation
Effect of the Sympathetic Nervous System.
135
Decreased saliva production
Effect of the Sympathetic Nervous System.
136
Increased heart rate & vasoconstriction
Effect of the Sympathetic Nervous System.
137
Bronchodilation
Effect of the Sympathetic Nervous System.
138
Decreased peristalsis & digestion
Effect of the Sympathetic Nervous System.
139
Decreased bile secretion
Effect of the Sympathetic Nervous System.
140
Bladder relaxation
Inhibits urination; effect of the Sympathetic Nervous System.
141
Acetylcholine (Ach)
Released by all preganglionic neurons & parasympathetic postganglionic neurons.
142
Norepinephrine (NE) & Epinephrine (EPI)
Released by sympathetic postganglionic neurons & adrenal medulla.
143
Alpha receptors (α1, α2)
α1: Vasoconstriction (increases BP), pupil dilation; α2: Inhibits neurotransmitter release (negative feedback).
144
Beta receptors (β1, β2, β3)
β1: Increases HR & contractility (heart); β2: Bronchodilation, vasodilation (skeletal muscles, lungs); β3: Lipolysis (fat metabolism).
145
Key Differences Between PNS & SNS
Feature: Primary Function, Heart Rate, Pupils, Saliva, Lungs, Digestion, Bladder, Bile Secretion, Adrenal Gland, Fiber Length.
146
PNS dominance at rest
Maintains baseline homeostasis.
147
SNS activation under stress
Prepares body for action.
148
Balance in ANS
Disruptions can lead to disorders (e.g., orthostatic hypotension, autonomic neuropathy).
149
Central Nervous System (CNS)
Develops: 3rd week of embryogenesis (neurulation) from the ectoderm layer.
150
Components of CNS
Brain + Spinal Cord
151
Spinal Cord
Connected to the brain through the foramen magnum.
152
Peripheral Nervous System (PNS)
12 cranial nerves (CNs) + 31 pairs of spinal nerves.
153
Cranial Nerves
Connected through foramina of the skull.
154
Neurons
Large body with a single nucleus and dendrites.
155
Unipolar Neuron
No dendrites, only an axon branch (e.g., primary afferent neurons in touch).
156
Bipolar Neuron
One axon + one dendrite (e.g., visual, auditory, and vestibular systems).
157
Multipolar Neuron
Numerous dendrites + one axon (most common in CNS).
158
Pseudo-unipolar Neuron
Develop as bipolar but merge to form unipolar neurons (e.g., nociception).
159
Axon
Myelinated for faster nerve signal transmission; terminates by releasing neurotransmitters (NTs).
160
White Matter
Myelinated axons.
161
Gray Matter
Neuron cell bodies, dendrites, unmyelinated axons, and neuroglia.
162
Astrocytes
Blood-brain barrier (BBB) formation.
163
Oligodendrocytes
Myelin sheath production in CNS (Schwann cells do this in PNS).
164
Microglia
CNS macrophages.
165
Ependyma
Line ventricles and circulate cerebrospinal fluid (CSF).
166
Cytoskeleton (Microtubules)
Crucial for NT release and transport, cell shape, and motility.
167
Composition of Microtubules
Alpha and beta tubulin form a lattice; gamma tubulin accelerates assembly.
168
Tau Protein
Stabilizes microtubules in axons; phosphorylated tau allows vesicle transport.
169
Action Potential (AP) Propagation
AP travels along axon from the cell body to the axon terminal.
170
Myelination
Increases nerve signal speed.
171
Short-term Synaptic Plasticity
Rule of 20 ms.
172
Paired Pulse Facilitation
Shorter interstimulus intervals (~20 ms) enhance NT release.
173
Meninges
Protective Layers around CNS.
174
Dura Mater
Outermost fibrous, loose coat.
175
Arachnoid Mater
Collagenous, loosely covers CNS.
176
Pia Mater
Delicate membrane, adheres closely to CNS tissues.
177
Subarachnoid Space
Contains CSF, located between arachnoid and pia mater.
178
CSF Function
Shock absorption, nutrient provision, waste removal, and homeostasis.
179
Production of CSF
By choroid plexus in ventricles.
180
Absorption of CSF
Through arachnoid granulations and meningeal lymphatics.
181
Cerebrovascular System
Vascular Supply to the CNS.
182
Spinal Cord Vascularization
Vascularized by vertebral arteries from subclavian arteries.
183
Brain Vascular Supply
Supplied by internal carotid arteries, with a high metabolic demand for oxygen and glucose.
184
Ischemic Stroke
Blockage of blood flow.
185
Hemorrhagic Stroke
Bleeding into the brain.
186
Blood-Brain Barrier (BBB)
Formed by continuous endothelial cells, regulated by astrocytes, prevents harmful substances from entering the brain.
187
Medulla Oblongata
Part of the hindbrain, controls autonomic functions (e.g., respiration, heart rate, digestion).
188
Pons
Connects the cerebrum to the cerebellum, controls sleep-wake cycles and respiration.
189
Cerebellum
Coordinates movement, balance, and motor learning.
190
Midbrain
Above pons, involved in sensory and motor functions, eye movement, and auditory/visual reflexes.
191
Diencephalon
Contains thalamus and hypothalamus.
192
Thalamus
Processes sensory and motor signals to the cerebral cortex.
193
Hypothalamus
Regulates autonomic, endocrine, and visceral functions (pituitary control).
194
Frontal Lobe
Voluntary movement, language expression, executive function.
195
Temporal Lobe
Contains hippocampus (memory) and amygdala (emotion and autonomic responses).
196
Parietal Lobe
Processes touch and spatial awareness.
197
Occipital Lobe
Visual processing (color, form, motion).
198
Gyri
Ridges of the cortex.
199
Sulci
Grooves between gyri.
200
Neocortex
Six-layered cortex, critical for high-level brain functions.
201
Gray Matter in Spinal Cord
Located at the center, processes sensory and motor information.
202
Dorsal Horn
Receives sensory input.
203
Ventral Horn
Projects motor output.
204
White Matter in Spinal Cord
Surrounds the gray matter, consists of myelinated axons that transmit signals to and from the brain.
205
Endocrinology
The study of hormones and their effects on the body.
206
Hormones
Substances secreted by endocrine glands that travel via the bloodstream to target tissues.
207
Endocrine glands
Specialized cells that secrete hormones directly into the bloodstream and lack ducts.
208
Exocrine glands
Glands that have ducts carrying products like saliva or sweat to a surface.
209
Peptide hormones
Chains of amino acids that are water-soluble, not orally active, have a fast onset, short half-life, stored as inactive precursors, and often synthesized and released upon stimulation.
210
Steroid hormones
Lipid-derived hormones that are lipophilic, can cross cell membranes, have a slow onset, long half-life, and are orally active.
211
Amino-acid derived hormones
Hormones derived from tyrosine and iodine that are lipophilic but transport in blood is protein-bound.
212
Hormonal action
The mechanism by which hormones bind to receptors and trigger responses in target cells.
213
Internal processes regulated by hormones
Metabolism, growth, development, reproduction, and mood.
214
Hormone potency
Hormones act over long distances and are potent even at low concentrations.
215
Endocrine roles of non-endocrine tissues
Some tissues like the liver and heart have endocrine roles but are not primarily classified as endocrine glands.
216
Peptide hormone action
Bind to receptors on the cell surface, triggering rapid responses.
217
Steroid hormone action
Bind to intracellular receptors and regulate gene expression.
218
Peptide hormone properties
Water-soluble, not orally active, fast onset, short half-life, stored as inactive precursors.
219
Steroid hormone properties
Lipophilic, can cross cell membranes, slow onset, long half-life, orally active.
220
Amino-acid derived hormone properties
Lipophilic, but transport in blood is protein-bound.
221
Half-life
The time it takes for the concentration of a substance in the body to reduce to half its initial value.
222
Hormonal stimulation
The process that triggers the synthesis and release of hormones.
223
Hormone transport
The method by which hormones travel through the bloodstream to reach target tissues.
224
T3
Active form of thyroid hormone.
225
T4
Inactive form of thyroid hormone, converted to T3 in tissues.
226
Nuclear receptors
Receptors for steroid hormones (e.g., estrogen).
227
GPCRs
G protein-coupled receptors for extracellular peptides.
228
Tyrosine kinase receptors
Receptors for amino acid-derived hormones like thyroid hormones.
229
Pituitary gland
Known as the 'master gland' because it controls other endocrine glands.
230
Anterior pituitary
Produces hormones like growth hormone (GH), TSH, ACTH, FSH, LH, and prolactin.
231
Posterior pituitary
Releases hormones like ADH (antidiuretic hormone) and oxytocin.
232
Hypothalamus
Controls the pituitary via releasing hormones (e.g., TRH for thyroid regulation).
233
Negative feedback loops
Regulate hormone release.
234
Thyroid gland
Regulates metabolism and is controlled by TSH (from the pituitary).
235
Calcitonin
Reduces blood calcium levels.
236
Thyroid hormone effects
Increases basal metabolic rate, affects carbohydrate, lipid, and protein metabolism, increases heart rate, stroke volume, and blood pressure, stimulates neurogenesis, skin proliferation, and hair growth.
237
Hyperthyroidism
Caused by Grave's disease or excessive thyroid hormone replacement, leads to 'sped up' effects (e.g., weight loss, heat intolerance).
238
Hypothyroidism
Caused by Hashimoto's thyroiditis or iodine deficiency, leads to 'slowed down' effects (e.g., fatigue, cold intolerance).
239
Adrenal glands
Located on top of the kidneys.
240
Inner medulla
Releases adrenaline and noradrenaline, controlled by sympathetic nervous system.
241
Outer cortex
Releases glucocorticoids (e.g., cortisol), which regulate stress response, metabolism, and sodium homeostasis.
242
Gonads
Testes produce testosterone; ovaries produce estrogen and progesterone.
243
Insulin
Lowers blood glucose.
244
Glucagon
Raises blood glucose.
245
Hormonal Feedback Loops
Most hormones are regulated by feedback mechanisms, which ensure homeostasis.
246
Hydrophilic hormones
Peptides that can't cross the cell membrane, acting on cell surface receptors.
247
Lipophilic hormones
Steroids that can cross the membrane and act on intracellular receptors.
248
Pleura
Double-layered serosa (parietal & visceral), cushioning and facilitating smooth lung movement.
249
Pleural Cavity
Fluid-filled space between pleurae, allowing lungs to move during breathing.
250
Characteristics for Gaseous Exchange
Thin alveolar membrane, large surface area, strong concentration gradients (O2 and CO2).
251
Airway Lining
Epithelial cells serve as a barrier for pathogens, goblet cells secrete mucus, and cilia move mucus and particles.
252
Nose
Filters, warms, and moistens air.
253
Mucus
Traps particles, cilia moves it out.
254
Olfactory Nerves
Chemical detection by smell.
255
Pathology (Nose)
Sinusitis, epistaxis (nosebleeds).
256
Pharynx
Muscular, connects nasal cavity to larynx and esophagus.
257
Larynx
Prevents aspiration via epiglottis.
258
Voice Production
Sound generation.
259
Cough Reflex
Air conditioning.
260
Trachea
Cartilage keeps airway open.
261
Smooth Muscle (Trachea)
For airway regulation.
262
Pathology (Trachea)
Triggers for bronchoconstriction.
263
Bronchi
Branches into smaller bronchioles ending at alveoli (gas exchange).
264
Lung Lobes
Left lung has 2 lobes, right lung has 3 lobes.
265
Alveoli
Thin-walled sacs for gas exchange.
266
Surfactant
Secretion reduces surface tension, prevents collapse.
267
Pathology (Alveoli)
Surfactant deficiency (e.g., NRDS).
268
Lung Compliance
Facilitated by elastic recoil and surfactant.
269
Fick's Law
Gas diffusion depends on surface area, membrane thickness, pressure difference.
270
Dalton's Law
Gas pressure is the sum of individual gas partial pressures.
271
Henry's Law
Gas solubility is proportional to partial pressure.
272
Hemoglobin Binding
Oxygen binds cooperatively to hemoglobin; carbon dioxide promotes O2 release via Bohr effect.
273
Bohr Effect
Active tissues produce CO2, leading to O2 release due to proton binding.
274
Cystic Fibrosis (CF)
Mutations in CFTR result in thick mucus due to impaired chloride and bicarbonate transport.
275
Mucus Composition
Water, mucins, proteins, lipids, electrolytes.
276
Airway Clearance
Mucus traps debris, removed by cilia.
277
Inhalation
Active process, diaphragm and intercostal muscles contract.
278
Exhalation
Passive process, elastic recoil of lungs.
279
Peripheral Chemoreceptors
Detect hypoxia, hypercapnia, and acidosis.
280
Central Chemoreceptors
Detect increased CO2 and H+ levels in CSF, leading to hyperventilation.
281
Autonomic Control
Vagus nerve (CN X) mediates reflexes and muscle coordination.
282
Physical Factors
Exercise, talking, coughing increase rate and depth of breathing.
283
Volitional Control
Hypothalamus influences respiratory rate during emotional stress.
284
Efferent Pathways
Coughing involves abdominal and intercostal muscles for forced exhalation.
285
Lung Function Tests
Evaluate pulmonary volumes and airflow.
286
Bronchial Dysfunction
Bronchoconstriction: Acetylcholine activates M3 receptors.
287
Bronchodilation
Adrenaline activates B2 receptors, leading to relaxation.
288
COPD
Caused by chronic inflammation and tissue damage (often linked to smoking, lack of alpha-1 antitrypsin).
289
Obstructive Conditions
Thickened mucus in CF and asthma, airway obstruction.
290
Inflammation
Bronchitis, asthma, and sinusitis cause mucus production and airway narrowing.
291
EKG polarization overview
PQRST.
292
Cardiac AP variation
Variation from other smooth muscle tissue (AV node excitability rebound rubber band effect) - Ca dependent.
293
Different receptors based on tissues
Includes neurotransmitters (NE, Epi), hormones (thyroid, catecholamines), low BP.
294
↓ HR
Parasympathetic activation (vagus nerve, ACh).
295
Stroke Volume (SV) Influencers
Factors affecting stroke volume.
296
Preload (EDV)
Volume of blood in ventricles at end of diastole.
297
↑ Preload (↑ EDV) → ↑ SV
Indicates that increased preload leads to increased stroke volume.
298
Causes of ↑ Preload
Hypervolemia, valve regurgitation, heart failure.
299
Afterload (Resistance)
Force heart must overcome to eject blood.
300
↑ Afterload → ↑ Workload → ↓ SV
Indicates that increased afterload leads to increased workload and decreased stroke volume.
301
Causes of ↑ Afterload
Hypertension, vasoconstriction.
302
Right Ventricle
Pumps blood to lungs
303
Left Ventricle
Pumps blood to body
304
Wall Thickness
Thin (Right Ventricle) and Thick (Left Ventricle)
305
Shape of Ventricles
Crescent (Right Ventricle) and Circular (Left Ventricle)
306
Pressure in Right Ventricle
Low
307
Pressure in Left Ventricle
High
308
Resistance in Right Ventricle
Low
309
Resistance in Left Ventricle
High
310
Cardiac Excitability
SA Node: Pacemaker; fires first due to highest excitability
311
AP Initiation
Na⁺ entry → Depolarization (not Ca²⁺ triggered)
312
Frank-Starling Law
More blood in (↑ EDV) → More stretch → Stronger contraction
313
Total Peripheral Resistance (TPR)
↑ TPR → More resistance → Harder to pump blood back
314
Blood Pressure Regulation
Blood return regulated by: Sympathetic activity, Skeletal muscles, ventilation
315
Venous Return Regulation
Sympathetic activation (venoconstriction), Skeletal muscle contractions (muscle pump), Respiratory movements (thoracic pump)
316
NE (α1 receptors)
Vasoconstriction (↑ BP, reduces flow to less active tissues)
317
Epi (β2 receptors)
Vasodilation (relaxes smooth muscle in active areas, e.g., muscles during exercise)
318
Renin-Angiotensin-Aldosterone (RAA) System
Regulates BP & fluid balance
319
Renin Mechanism
↓ BP → Kidneys release renin → Converts angiotensinogen → angiotensin I → ACE converts angiotensin I → angiotensin II
320
Effects of Angiotensin II
Vasoconstriction → ↑ BP; Aldosterone release → Na⁺ & water retention (↑ blood volume)
321
Urinary Tract Function
Filters blood and excretes metabolic products; Regulates pH through acid-base balance
322
Kidneys Location
Located in the abdominal cavity: Left kidney: Inferior to spleen; Right kidney: Inferior to liver
323
Kidneys Functions
Regulate blood volume & pressure, Water & ion excretion, Electrolyte management, Plasma pH control, Nutrient absorption, Red blood cell biosynthesis, Bone health, Excretion of metabolic & foreign toxins
324
Kidney Structure - Cortex
Outer light region; Contains Bowman's capsule; Short loop of Henle
325
Juxtamedullary Region
Located at the cortex-medulla junction; Contains long loop of Henle & peritubular capillaries (vasa recta); Important in the countercurrent mechanism
326
Afferent arteriole
Blood vessel that carries blood to the glomerulus.
327
Glomerulus
Network of capillaries located at the beginning of a nephron.
328
Efferent arteriole
Blood vessel that carries blood away from the glomerulus.
329
Proximal convoluted tubule
Segment of the nephron where reabsorption of water, ions, and nutrients occurs.
330
Descending limb (Loop of Henle)
Part of the nephron that allows for the reabsorption of water.
331
Loop of Henle
U-shaped section of the nephron that concentrates urine.
332
Ascending limb (Loop of Henle)
Part of the nephron that allows for the reabsorption of sodium and chloride ions.
333
Collecting duct
Final segment of the nephron that collects urine from multiple nephrons.
334
Net Filtration Pressure
Blood hydrostatic pressure (55 mmHg) - Filtrate hydrostatic pressure (15 mmHg) - Oncotic pressure (30 mmHg) = 10 mmHg.
335
Mean Arterial Pressure (MAP)
Average blood pressure in a person's arteries during one cardiac cycle, normal range: 70-100 mmHg.
336
MAP formula
MAP = Diastolic Pressure + 1/3 (Systolic - Diastolic).
337
Glomerular Filtration Rate (GFR)
Measures the amount of substance secreted into urine concentration, normal range: 90-120 mL/min/1.73m^2.
338
Myogenic Response
Response of afferent artery to increased blood pressure leading to vasoconstriction.
339
Tubuloglomerular Feedback
Mechanism where increased perfusion leads to NaCl detection and vasoconstriction of afferent arteriole.
340
Neural Control
Response to low blood volume involving norepinephrine release and vasoconstriction of arterioles.
341
Renin-Angiotensin-Aldosterone System (RAAS)
Hormonal system that regulates blood pressure and fluid balance.
342
Atrial Natriuretic Peptide (ANP)
Hormone released in response to increased blood volume that promotes vasodilation and increases GFR.
343
Ureters
Two tubes that transport urine from kidneys to bladder.
344
Bladder
Organ located in the pelvic cavity that stores urine before excretion.
345
Urethra
Tube through which urine is expelled; functions differ between males and females.
346
Glomerular Filtration
Process occurring in the renal corpuscle that filters unbound small molecules.
347
Tubular Reabsorption
Process where substances are reabsorbed from the tubular fluid back into the blood.
348
Na+ Reabsorption
Process of sodium reabsorption against concentration gradient via Na+/K+ pump.
349
Water Reabsorption
Process of water being reabsorbed through aquaporins and osmosis.
350
Nutrient & Ion Reabsorption
Process coupled with Na+ transport via luminal membrane transporters.
351
Tubular Secretion
Removes protein-bound drugs, metabolites, toxins, & waste products.
352
Excretes nitrogenous compounds
Urea, creatinine, ammonia, uric acid.
353
Secretes organic acids and bases
Organic acids (acidic drugs) & organic bases (alkaline drugs).
354
Glomerulus
Filtration.
355
Proximal Tubule
Reabsorption (water, electrolytes), Secretion (protein-bound molecules, acids, bases, drugs, metabolites).
356
Loop of Henle
Reabsorption (water & electrolytes).
357
Distal Tubule
Na+ reabsorption in exchange for K+ or H+.
358
Collecting Duct
Water reabsorption under ADH influence.
359
Osmolarity
Measures dissolved particles per water volume (mOsm/kg).
360
Normal 24-hr Osmolarity
500-800 mOsm/kg.
361
Osmolarity after 12-14 hrs water restriction
850 mOsm/kg.
362
High Osmolarity Causes
Dehydration, SIADH, Glycosuria (diabetes, SGLT-2 inhibitors), Hypernatremia, High protein diet.
363
Low Osmolarity Causes
Diabetes insipidus, ADH deficiency, Overhydration, Renal insufficiency, Glomerulonephritis.
364
Specific Gravity
Normal: 1.005 - 1.03.
365
Specific Gravity of 1.035
Indicates Dehydration.
366
Specific Gravity of 1.015
Indicates Hypovolemia.
367
Countercurrent Multiplier
Loop of Henle & collecting duct; Interstitial osmolality increases down the loop.
368
ADH Influence on Urine
Overhydration → Reduced ADH → Dilute urine; Dehydration → ADH release → Water reabsorption → Concentrated urine.
369
Urea Recycling
Helps maintain medullary interstitial osmolality (~600 mOsm).
370
Micturition
Initiated by bladder stretch.
371
Sacral Micturition Center
Coordinates bladder & sphincter.
372
Pontine Micturition Center
Switches bladder modes.
373
Cerebral Cortex in Micturition
Inhibits sacral center until urination is appropriate.
374
Acidosis
pH <6.8; CNS depression, excess H+ secretion, HCO3- reabsorption.
375
Alkalosis
pH >7.8; Excess HCO3- secretion, H+ reabsorption.
376
Tubular reabsorption of Na+
Against [] gradient through Na+/K+ pump.
377
H2O reabsorption
Aquaporins + osmosis.
378
Liver Functions Overview
Includes metabolic, synthetic, storage, and homeostatic functions.
379
Carbohydrate Metabolism
Glycogen storage, conversion of galactose/fructose to glucose, gluconeogenesis.
380
Protein Metabolism
Involves synthesis and breakdown of proteins.
381
Fat Metabolism
Involves synthesis and breakdown of fats.
382
Drug Metabolism Phase I
Reactions: Oxidation (via CYP450), Reduction, Hydrolysis.
383
Purpose of Phase I Metabolism
Converts parent drugs into more polar (water-soluble) metabolites by adding functional groups (-OH, -SH, -NH2).
384
CYP450 Enzymes
Handles lipophilic substances, xenobiotic metabolism, steroid hormone regulation.
385
Phase II Metabolism
Conjugation Reactions: Glucuronidation, Acetylation, Sulfation.
386
Key Considerations for Phase II Metabolism
Deficiency in acetylation (slow acetylators) → prolonged/toxic drug response.
387
Innate Immune System Cells
Macrophages, Neutrophils, Dendritic Cells, Natural Killer (NK) Cells.
388
Chemokines
Peptides that stimulate migration of cells (chemotaxis).
389
Epithelial Barriers
Physical barrier against external threats: Skin, GI, Respiratory, Urogenital Tracts.
390
T-Cells
Recognize antigenic protein fragments via MHC molecules on APCs.
391
B-Cells
Secrete antibodies to recognize foreign molecules (memory-based).
392
Major Histocompatibility Complex (MHC)
Essential for acquired immunity & histocompatibility.
393
CD4+ Helper T-Cells
Subtypes include Th1, Th2, Th17, Treg, Tfh.
394
B-Cell Activation
B-Cells only produce antibodies, do not kill.
395
Primary vs Secondary Immune Response
Primary: Maximal response within 10 days; Secondary: Faster (4 days) due to memory cells.
396
Innate Immunity
First line of defense against pathogens.
397
Macrophages
Engulf and destroy bacteria and debris.
398
Neutrophils
Short-lived cells, aggressive in fighting infections.
399
Dendritic Cells
APCs that present antigens to T-cells.
400
Natural Killer Cells
Kill infected cells with reduced MHC class I.
401
Chemokines
Peptides that induce cell migration via chemotaxis.
402
Epithelial Barriers
Physical barriers protecting against external threats.
403
Stratum Corneum
Waterproof outer layer of skin.
404
Mucociliary Escalator
Mechanism trapping pathogens in airways.
405
Adaptive Immunity
Involves T-cells and B-cells for specific responses.
406
Pattern Recognition Receptors
Bind to PAMPs, activating immune responses.
407
Cytoplasmic PRRs
Examples include NOD1 and NOD2 receptors.
408
Toll-like Receptors
Membrane-bound PRRs recognizing pathogens.
409
Complement System
Enhances immune response through opsonization and lysis.
410
Classical Pathway
Activated by antibody-antigen complexes.
411
Alternative Pathway
Triggered by microbial surfaces lacking inhibitors.
412
Mannose-binding Lectin Pathway
Activated by specific carbohydrate patterns.
413
Antigen-Presenting Cells
Cells that present antigens to T-cells.
414
Major Histocompatibility Complex
Essential for antigen presentation and immune response.
415
MHC I
Presents endogenous antigens to CD8+ T-cells.
416
MHC II
Presents exogenous antigens to CD4+ T-cells.
417
CD4+ Helper T-Cells
Assist in activating B-cells and other T-cells.
418
B-Cell Activation
Triggered by antigen binding and T-cell help.
419
Class Switch Recombination
B-cells change antibody isotype based on signals.
420
Primary Immune Response
Initial response takes up to 10 days.
421
Secondary Immune Response
Faster response due to memory cells.
422
Tolerance
Immune system's non-reactivity to self-antigens.
423
Regulatory T-Cells
Maintain self-tolerance and prevent autoimmunity.
424
Innate Immunity
First line of defense against pathogens.
425
Macrophages
Engulf and destroy pathogens and debris.
426
Neutrophils
Short-lived cells that attack bacteria aggressively.
427
Dendritic Cells
APCs that present antigens to T-cells.
428
Natural Killer Cells
Target and kill virally infected or tumor cells.
429
Polymorphonuclear Leukocytes
Aggressive leukocytes with multilobed nuclei.
430
Chemokines
Peptides that induce cell migration during inflammation.
431
Epithelial Barriers
Physical barriers like skin and mucous membranes.
432
Stratum Corneum
Keratin-rich outer layer of skin.
433
Mucociliary Escalator
Mechanism trapping pathogens in airways.
434
Adaptive Immunity
Specific immune response involving T and B cells.
435
T-Cells
Recognize antigens via MHC molecules on APCs.
436
B-Cells
Produce antibodies against foreign molecules.
437
Memory System
Basis for long-lasting immunity from vaccination.
438
Pattern Recognition Receptors
Bind to PAMPs to initiate immune response.
439
Complement System
Enhances immune response and clears microbes.
440
Opsonization
Coating pathogens to enhance phagocytosis.
441
Major Histocompatibility Complex
MHC molecules present antigens to T-cells.
442
CD4+ T-Cells
Helper T-cells that assist other immune cells.
443
CD8+ T-Cells
Cytotoxic T-cells that kill infected cells.
444
Class Switch Recombination
B-cells switch antibody isotypes based on signals.
445
Primary Immune Response
Initial response takes up to 10 days.
446
Secondary Immune Response
Faster response due to memory cells, within 4 days.
447
Tolerance
Immune system's non-reactivity to self-antigens.
448
Regulatory T-Cells
Maintain tolerance and prevent autoimmunity.
449
Stomach pH
Ranges from 1.0 to 2.0, highly acidic.
450
Duodenum pH
Maintains a pH of 6.1 for digestion.
451
Small Intestine pH
Middle section has a pH of 7.1.
452
Distal Small Intestine pH
Reaches pH 7.5, affecting drug solubility.
453
Cecum pH
Maintains a pH of 6.0, impacting microbes.
454
Fluid Absorption
Most absorption occurs in the colon.
455
Osmosis in GI Tract
Fluid movement follows ion concentration gradients.
456
Glycogen storage
Storage of glucose in liver as glycogen.
457
Gluconeogenesis
Synthesis of glucose from non-carbohydrate sources.
458
Bilirubin Metabolism
Processing and excretion of bilirubin from hemoglobin.
459
Kupffer Cells
Liver macrophages involved in immune response.
460
Fat-Soluble Vitamins
Vitamins A, D, E, K, and B12 stored in liver.
461
Albumin
Protein that maintains oncotic pressure in blood.
462
Clotting Factors
Proteins essential for blood coagulation.
463
Fibrinogen
Precursor to fibrin, crucial for blood clotting.
464
Bile Production
Synthesis of bile for digestion and absorption.
465
CYP450 Enzymes
Enzymes involved in drug metabolism and detoxification.
466
Phase I Metabolism
Initial drug metabolism involving oxidation and reduction.
467
Phase II Metabolism
Conjugation reactions that enhance drug excretion.
468
Enterohepatic Circulation
Recycling of bile salts between liver and intestine.
469
Common Hepatic Duct
Duct connecting liver to gallbladder for bile transport.
470
Common Bile Duct
Duct merging cystic and hepatic ducts for bile flow.
471
Drug Clearance
Elimination of drugs and toxins from the body.
472
Insulin Metabolism
Regulation of blood glucose levels by insulin.
473
Steroid Hormone Metabolism
Processing of steroid hormones in the liver.
474
Fat Metabolism
Breakdown and synthesis of fatty acids and lipids.
475
Nutrient Homeostasis
Liver's role in maintaining nutrient balance.
476
Drug Half-Life
Time taken for drug concentration to halve.
477
Urinary Tract Function
Filters blood and excretes metabolic waste.
478
Acidosis
Condition causing bradycardia and hyperventilation.
479
Edema Treatment
Regulated fluids essential for managing edema.
480
Hematopoiesis
Formation of blood cellular components.
481
Kidneys
Organs regulating blood volume and pressure.
482
Kidney Weight
Each kidney weighs approximately 150g.
483
Electrolyte Management
Regulates ions like Na+, K+, and Ca2+.
484
Plasma pH Control
Filters H+ and HCO3- to maintain pH.
485
Erythropoietin
Hormone stimulating red blood cell production.
486
Renal Arteries
High blood supply to kidneys via these vessels.
487
Cortex
Outer region of the kidney containing Bowman's capsule.
488
Juxtamedullary Region
Site of long loop of Henle and vasa recta.
489
Net Filtration Pressure
Calculated as 10 mmHg in glomerulus.
490
Mean Arterial Pressure (MAP)
Normal range: 70-100 mmHg.
491
Glomerular Filtration Rate (GFR)
Normal range: 90-120 mL/min/1.73m^2.
492
Myogenic Response
Afferent artery constricts due to increased BP.
493
Tubuloglomerular Feedback
Macula Densa regulates GFR via NaCl sensing.
494
Renin-Angiotensin-Aldosterone System (RAAS)
Hormonal control increasing BP and GFR.
495
Atrial Natriuretic Peptide (ANP)
Promotes Na+ and water excretion when blood volume rises.
496
Ureters
Transport urine from kidneys to bladder.
497
Bladder
Stores urine before excretion.
498
Urethra
Conducts urine; dual function in males.
499
Urine Formation
Includes glomerular filtration, reabsorption, and secretion.
500
Countercurrent Multiplier
Mechanism increasing interstitial osmolality in kidneys.
501
Specific Gravity
Normal range: 1.005 - 1.03.
502
Micturition
Urination process initiated by bladder stretch.
503
Pleura
Double-layered membrane cushioning lung movement.
504
Pleural Cavity
Fluid-filled space enabling lung expansion.
505
Alveolar Membrane
Thin barrier facilitating gas exchange.
506
Surface Area
Larger area enhances gas exchange efficiency.
507
Concentration Gradients
Difference in gas concentrations driving diffusion.
508
Gas Exchange Function
Regulates blood pH and exchanges gases.
509
Epithelial Cells
Barrier against pathogens in airways.
510
Goblet Cells
Secrete mucus to trap particles.
511
Cilia
Hair-like structures moving mucus out.
512
Nose Functions
Filters, warms, and moistens inhaled air.
513
Pharynx
Muscular tube connecting nasal cavity to larynx.
514
Larynx
Voice production and prevents aspiration.
515
Trachea
Cartilage structure maintaining open airway.
516
Bronchi
Branches leading to bronchioles and alveoli.
517
Lung Lobes
Left lung has 2, right has 3.
518
Alveoli
Sacs for gas exchange, secretes surfactant.
519
Surfactant
Reduces surface tension, prevents alveolar collapse.
520
Lung Compliance
Ability to expand due to surfactant.
521
Fick's Law
Diffusion depends on area, thickness, pressure.
522
Dalton's Law
Total pressure equals sum of partial pressures.
523
Henry's Law
Gas solubility proportional to partial pressure.
524
Bohr Effect
CO2 production enhances O2 release from hemoglobin.
525
Cystic Fibrosis
Thick mucus due to CFTR mutations.
526
Neural Control of Breathing
Medulla and pons regulate rhythm and depth.
527
Ventilation Control Factors
Exercise and emotions affect breathing rate.
528
PQRST
Electrocardiogram waveform representing heart activity.
529
Cardiac Action Potential
Electrical impulse variation in heart muscle cells.
530
AV Node
Heart's electrical relay station; influences excitability.
531
Parasympathetic Activation
Decreases heart rate via vagus nerve and ACh.
532
Stroke Volume (SV)
Volume of blood ejected by heart per beat.
533
Preload (EDV)
Blood volume in ventricles at diastole's end.
534
Afterload
Resistance heart must overcome to eject blood.
535
Frank-Starling Law
Increased EDV leads to stronger heart contractions.
536
Right Ventricle
Pumps deoxygenated blood to lungs; thin walls.
537
Left Ventricle
Pumps oxygenated blood to body; thick walls.
538
Total Peripheral Resistance (TPR)
Overall resistance against blood flow in circulation.
539
Sympathetic Activity
Increases heart rate and blood pressure.
540
Venous Return Regulation
Mechanisms controlling blood return to heart.
541
Renin-Angiotensin-Aldosterone System
Hormonal system regulating blood pressure and fluid.
542
Vasoconstriction
Narrowing of blood vessels; increases blood pressure.
543
Vasodilation
Widening of blood vessels; decreases blood pressure.
544
Skeletal Muscle Pump
Muscle contractions aiding venous blood return.
545
Thoracic Pump
Pressure changes in thorax aiding venous return.
546
Catecholamines
Hormones like epinephrine affecting heart function.
547
Hypervolemia
Increased blood volume; raises preload.
548
Hypertension
High blood pressure; increases afterload.
549
Pleura
Double-layered serosa cushioning lung movement.
550
Pleural Cavity
Fluid-filled space between pleurae for lung movement.
551
Alveolar Membrane
Thin barrier facilitating gas exchange.
552
Surface Area
Lungs have large area for efficient gas exchange.
553
Concentration Gradients
Differences in O2 and CO2 levels drive exchange.
554
Goblet Cells
Secrete mucus in airways and gastrointestinal tract.
555
Cilia
Hair-like structures moving mucus and particles.
556
Nose
Filters, warms, and moistens inhaled air.
557
Olfactory Nerves
Detect chemicals for the sense of smell.
558
Pharynx
Muscular tube connecting nasal cavity to larynx.
559
Larynx
Voice production and prevents aspiration.
560
Trachea
Cartilage-supported tube keeping airway open.
561
Bronchi
Branches leading to smaller bronchioles and alveoli.
562
Lung Lobes
Left lung has 2 lobes; right has 3.
563
Alveoli
Thin-walled sacs where gas exchange occurs.
564
Surfactant
Reduces surface tension in alveoli, preventing collapse.
565
Fick's Law
Gas diffusion depends on area, thickness, pressure.
566
Dalton's Law
Total gas pressure equals sum of partial pressures.
567
Henry's Law
Gas solubility proportional to its partial pressure.
568
Bohr Effect
CO2 production promotes O2 release from hemoglobin.
569
Cystic Fibrosis
Genetic disorder causing thick mucus due to CFTR mutations.
570
Inhalation
Active process involving diaphragm and intercostal muscles.
571
Exhalation
Passive process driven by lung elastic recoil.
572
Chemoreceptors
Detect O2 and CO2 levels, influencing breathing.
