systems Flashcards
(143 cards)
1
Q
What is the CNS composed of?
A
The brain and spinal cord.
2
Q
What makes up the peripheral nervous system?
A
Cranial nerves and spinal nerves.
3
Q
What is the function of motor pathways?
A
Carry information from CNS to muscles, causing movement.
4
Q
What are autonomic motor functions?
A
Involuntary processes like heart rate and gut contractions.
5
Q
What are the divisions of the autonomic nervous system?
A
Sympathetic and parasympathetic divisions.
6
Q
What is the somatic nervous system?
A
Controls voluntary movements.
7
Q
What are sensory pathways?
A
Carry information into the CNS from the body.
8
Q
What is the difference between afferent and efferent pathways?
A
Afferent: sensory to CNS; Efferent: motor from CNS.
9
Q
What is the role of the forebrain?
A
Controls high-level functions; includes cortex, thalamus, hypothalamus, etc.
10
Q
What structures are in the hindbrain?
A
Brainstem and cerebellum.
11
Q
What does the thalamus do?
A
Processes and relays sensory information.
12
Q
What is the function of the hypothalamus?
A
Regulates autonomic functions and links nervous and endocrine systems.
13
Q
What hormone is released by the pineal gland?
A
Melatonin.
14
Q
What is the limbic system responsible for?
A
Regulating emotional responses.
15
Q
What is the function of the hippocampus?
A
Learning, memory, and some emotional regulation.
16
Q
What does the cerebellum control?
A
Coordination, posture, and motor learning.
17
Q
What arteries supply the brain?
A
Vertebral and carotid arteries.
18
Q
What is the spinal cord’s function?
A
Transmits signals between brain and body and coordinates reflexes.
19
Q
What is decussation?
A
Crossing over of sensory or motor pathways to the opposite side.
20
Q
What is a dermatome?
A
An area of skin linked to a specific spinal nerve.
21
Q
What are cranial nerves?
A
Peripheral nerves that control sensory and motor functions of the head.
22
Q
What are neurons?
A
Basic structural unit of the nervous system, specialized for communication.
23
Q
What are synapses?
A
Junctions where neurons communicate via neurotransmitters.
24
Q
What are dendrites and axons?
A
Dendrites receive signals; axons send signals.
25
What is the resting membrane potential?
The voltage difference across a cell membrane at rest (~ -50 to -90 mV).
26
What causes depolarisation?
Opening of voltage-gated sodium channels.
27
What causes repolarisation?
Opening of voltage-gated potassium channels after depolarisation.
28
What is myelination?
Insulation of axons by myelin to speed up signal conduction.
29
What is the node of Ranvier?
Unmyelinated gaps with high ion channel density for action potential jumping.
30
Which cell produces myelin in the CNS?
Oligodendrocyte.
31
What do A-delta and C fibres do?
A-delta: fast pain; C fibres: slow, dull pain.
32
What are neurotransmitters?
Chemical messengers that transmit signals across synapses.
33
What is glutamate?
The major excitatory neurotransmitter.
34
What is GABA?
The major inhibitory neurotransmitter.
35
What is an EPSP?
Excitatory post-synaptic potential that may trigger an action potential.
36
What is an IPSP?
Inhibitory post-synaptic potential that reduces the chance of action potential.
37
What is temporal summation?
Multiple EPSPs from a single neuron over time.
38
What is spatial summation?
EPSPs from multiple neurons arriving at different dendrites.
39
What is the immune system?
A collection of cells, tissues, and molecules that mediate immunity.
40
What are the main roles of the immune system?
Fighting infection, wound healing, cancer surveillance, and maintaining homeostasis.
41
What does the immune system tolerate?
Commensal organisms, harmless foreign molecules (e.g. food), and healthy self cells.
42
What are primary immunodeficiencies?
Genetic defects causing lack of immune cells.
43
What are secondary immunodeficiencies?
Defects due to infections, medication, or malnutrition.
44
What are the primary lymphoid organs?
Bone marrow and thymus.
45
What are secondary lymphoid organs?
Spleen, lymph nodes, mucosal and cutaneous lymphoid tissues.
46
What are the two main branches of the immune response?
Innate and adaptive immunity.
47
What are examples of innate immune cells?
Neutrophils, monocytes, dendritic cells, eosinophils, basophils, mast cells.
48
What do lymphoid progenitors give rise to?
Lymphocytes like B and T cells (adaptive immunity).
49
What are complement proteins?
Proteins that induce cell death and inflammation via a cascade mechanism.
50
What do cytokines do?
They mediate immune communication and inflammatory responses.
51
What are antibodies?
Proteins produced by B cells that target and neutralise pathogens.
52
What are hallmarks of innate immunity?
Speed, short duration, repetitive response, and no memory.
53
How does the innate immune system recognise pathogens?
Using Pattern Recognition Receptors (PRRs) to detect PAMPs and DAMPs.
54
What is phagocytosis?
Ingestion and destruction of microbes by neutrophils and macrophages.
55
What are NETs?
Neutrophil extracellular traps used to kill microbes outside the cell.
56
What do eosinophils do?
Release granules to kill large parasites like helminths.
57
What do NK cells do?
Kill virus-infected and cancer cells using cytotoxic granules.
58
What is inflammation?
A tissue response that delivers immune mediators to infection sites.
59
What causes redness and swelling in inflammation?
Histamine and cytokine release from mast cells increases vascular permeability.
60
How do leukocytes exit blood vessels?
Roll, adhere via selectins, extravasate, and migrate to tissue.
61
What guides leukocytes to infection sites?
Chemokines that create a concentration gradient.
62
What is acute inflammation?
A beneficial short-term response to infection or injury.
63
What is chronic inflammation?
A prolonged immune response that can lead to diseases like RA or cancer.
64
How can pathogens evade the innate immune system?
Using protective structures like polysaccharide capsules.
65
What is the role of dendritic cells?
Capture microbes and activate T cells to link innate and adaptive immunity.
66
What is the adaptive immune system also called?
Specific or acquired immunity.
67
What are the main cells of the adaptive immune system?
Lymphocytes – B cells and T cells.
68
How many antigens can adaptive immune cells recognize?
Up to 10 trillion, using diverse antigen-specific receptors.
69
What is the role of B cells?
Produce antibodies and mediate humoral immunity.
70
What is the B cell receptor (BCR)?
A membrane-bound immunoglobulin that binds to antigens.
71
What happens when a B cell is activated?
It proliferates and differentiates into plasma cells and memory B cells.
72
What are the five antibody isotypes?
IgM, IgD, IgG, IgE, IgA.
73
What is IgM?
First antibody produced by naive B cells; pentamer structure when secreted.
74
What is IgG?
Most abundant in serum; crosses placenta; strong antiviral and antibacterial defense.
75
What is IgE?
Involved in defense against parasites and allergic responses.
76
What is IgA?
Most abundant at mucosal surfaces, first line of defense in gut and airways.
77
How are T cells activated?
By antigen presentation via MHC molecules from dendritic cells.
78
What is the T cell receptor (TCR)?
A membrane-bound receptor that recognizes antigen on MHC molecules.
79
What are MHC molecules also known as?
HLA molecules (important in transplant compatibility).
80
What are helper T cells?
T cells that produce cytokines to assist other immune cells.
81
What are cytotoxic T cells?
T cells that directly kill infected or abnormal cells.
82
What are memory T cells?
Long-lived cells that respond rapidly upon re-exposure to the same antigen.
83
What is central tolerance?
Deletion of self-reactive cells during development in thymus or bone marrow.
84
What is peripheral tolerance?
Suppression of self-reactive cells in tissues by regulatory cells.
85
What causes autoimmune diseases?
Genetic predisposition and environmental triggers like infections or trauma.
86
What is epigenetic memory in immune cells?
Changes that allow faster and more potent secondary responses.
87
What is immunotherapy?
Cancer treatment that manipulates the immune system, e.g., CAR T cells.
88
What is CAR T cell therapy?
Genetically engineered T cells designed to target and kill cancer cells.
89
What immune cells are targeted in autoimmune diseases?
B cells (e.g., lupus), T cells (e.g., type 1 diabetes), cytokines, integrins.
90
What is humoral immunity?
Immunity involving antibodies and secreted molecules in body fluids.
91
What is cell-mediated immunity?
T cell-driven immunity targeting infected or abnormal cells.
92
What are the two main circuits in the circulatory system?
Pulmonary: heart ⇄ lungs; Systemic: heart ⇄ body.
93
What is the function of the lymphatic system in circulation?
Returns leaked fluid to circulation, aids immunity.
94
What defines a closed circulatory system?
Blood is confined to vessels, separated from tissues.
95
What is the rule for arteries vs veins?
Arteries carry blood away from the heart; veins carry it toward.
96
What is the structure and function of capillaries?
One cell thick, site of gas/nutrient exchange.
97
What are the components of blood?
Plasma (55%) and formed elements (RBCs, WBCs, platelets) (45%).
98
What stimulates red blood cell production?
Erythropoietin (EPO), secreted by kidneys in response to hypoxia.
99
How do athletes misuse EPO?
To enhance oxygen delivery (blood doping), increasing performance.
100
What is the function of the tricuspid and bicuspid valves?
Prevent backflow: Tricuspid (RA → RV), Bicuspid/Mitral (LA → LV).
101
What are the semilunar valves?
Pulmonary (RV → pulmonary artery), Aortic (LV → aorta).
102
What initiates the heart’s electrical signal?
SA node (pacemaker) in the right atrium.
103
What is the function of the AV node?
Delays impulse to allow full atrial contraction.
104
What are Purkinje fibers?
Conduct signal through ventricles, causing contraction.
105
What is diastole vs systole?
Diastole = relaxation/filling; Systole = contraction/ejection.
106
What causes the heart sounds 'lub-dub'?
S1 = AV valves closing; S2 = SL valves closing.
107
What is stroke volume (SV)?
Amount of blood ejected per beat (~70 mL).
108
What is cardiac output (CO)?
SV × heart rate; e.g. 70 mL × 72 bpm = 5.4 L/min.
109
What factors influence blood pressure?
Heart contraction, arterial elasticity, vessel resistance.
110
What is normal blood pressure?
120/80 mmHg (systolic/diastolic).
111
What is postural hypotension?
Drop in BP when standing still due to reduced venous return.
112
How is blood returned from the legs to the heart?
Via venous valves and skeletal muscle pumps.
113
What is capillary diffusion?
Small molecules move across endothelium.
114
What is transcytosis?
Vesicle transport of large molecules across capillary endothelium.
115
What is bulk flow?
Fluid leaks through large capillary pores, e.g., in kidneys.
116
What are the functions of the lymphatic system?
Returns fluid, absorbs fats, immune surveillance.
117
What is the role of lymph nodes?
Filter pathogens and support immune cell activity.
118
What makes breathing unique compared to circulation?
Breathing can be voluntary; normally it's automatic.
119
What is the total surface area of alveoli equivalent to?
A tennis court.
120
What is the pathway of air through the respiratory system?
Nasal cavity → pharynx → epiglottis → larynx → trachea → bronchi → bronchioles → alveoli.
121
What role does the epiglottis play?
Prevents food from entering the trachea.
122
What is the functional unit of the lungs?
Alveoli.
123
What are the roles of alveolar Type I and Type II cells?
Type I: gas diffusion; Type II: secrete surfactant.
124
What is the purpose of surfactant?
Reduces surface tension and prevents alveolar collapse.
125
What is tidal volume?
The volume of a normal breath (~500 mL).
126
What is residual volume?
Air remaining after full exhalation (~1.2 L).
127
What is vital capacity?
Maximum air exhaled after maximum inhalation.
128
What muscles are involved in inspiration?
Diaphragm and intercostal muscles.
129
How does pressure change during inspiration?
Chest expands → pressure drops → air flows in.
130
How is most oxygen transported in the blood?
98% bound to haemoglobin.
131
What is the PO₂ in alveoli and tissues?
Alveoli: ~100 mmHg; Tissues: ~40 mmHg.
132
How is most carbon dioxide transported?
70% as bicarbonate (HCO₃⁻), 23% on Hb, 7% dissolved.
133
What enzyme facilitates CO₂ to HCO₃⁻ conversion?
Carbonic anhydrase in red blood cells.
134
How does the body respond to high CO₂ levels?
↓ pH sensed → ↑ breathing rate.
135
What is an obstructive lung disease?
Diseases with narrowed airways and difficulty exhaling (e.g., asthma).
136
What is a restrictive lung disease?
Diseases limiting lung expansion (e.g., fibrosis).
137
What is emphysema?
Destruction of alveoli → ↓ surface area for gas exchange.
138
What is pulmonary edema?
Fluid in alveolar spaces → ↑ diffusion distance.
139
What is pneumothorax?
Air in pleural space → collapsed lung.
140
What is a V/Q mismatch?
Poor alignment of ventilation and perfusion.
141
What causes sneezing?
Nasal receptors trigger a forced air release through the nose.
142
What causes hiccups?
Involuntary diaphragm contraction + vocal cord closure.
143
What does the gag reflex do?
Prevents aspiration by reacting to pharyngeal stimulation.
