The Cardiovascular System Flashcards
1
Q
Describe blood transport
A
- O2 carried from lungs to body tissues
- CO2 carried from tissues to lungs to be removed
- Nutrients carried from digestive tract to body tissues
- Metabolic wastes carried to kidneys for removal
- Hormones carried from endocrine cells to target organs
- Stem cells transported from bone marrow to tissues, lodge and mature
2
Q
Describe the role of blood in inflammation
A
- WBC: destroy microorganisms and cancer cells
- Antibodies: neutralize toxins, destroy pathogens
- Platelets: release factors to intitiate blood clotting and to minimize blood loss
3
Q
Describe the role of blood in regulation
A
- Stabilizes pH of extracellular fluids by buffering acids and bases
- Regulates body temperature by shifting blood flow (heat loss: routes blood to skin; heat conservation: retain blood deeper in the body)
4
Q
Components of blood
A
- Matrix of blood plasma: ~50% of blood volume
- Plasma holds seven formed elements
- RBC (erythrocytes)
- WBC (five types of leukocytes)
- Platelets (fragments of bone marrow cells)
5
Q
Name the five types of leukocytes
A
- Granulocytes (specific granules present in cytoplasm): neutrophils, eosinophils, basophils
- Agranulocytes: lymphocytes, monocytes
6
Q
Components of blood plasma
A
- Water (~92%)
- Proteins
- Albumin: buffers blood pH
- Globulins: immune system
- Fibrinogen: becomes fibrin used in blood clotting
- Nutrients
- Electrolytes
- Hormones
- Gases
- Nitrogenous wastes
6
Q
Functions of RBC (erythrocytes)
A
- Transports O2 from lungs to body tissues
- Removes CO2 from body tissues to lungs
7
Q
Properties of RBC (erythrocytes)
A
- No nucleus or internal structures
- No mitochondria ➡ uses anaerobic respiration
- Biconcave in shape, sunken in the centre
- Glycolipids in plasma membrane determines blood type
8
Q
What is haemoglobin?
A
- Iron containing gas transport proteins in RBCs
- Globins: two alpha protein chains, two beta protein chains
- Heme: non-proteins bound to each protein chain
- O2 binds to the iron atom, up to 4 transport
- CO2 binds to the globins
9
Q
Describe haematopoiesis and erythropoiesis
A
- Haematopoietic tissues produce RBCs
- Red bone marrow contains haematopoietic stem cells (HSC) ➡ forms RBCs, WBCs, or platelets
-
Erythropoiesis
- HSC differentiate into erythrocyte colony forming units (ECFU)
- Erythropoietin (produced by kidneys) causes ECFUs to become RBCs
- RBCs have a lifespan of 120 days
10
Q
How are blood types determined?
A
- Glycolipids on the plasma membrane of RBCs
- Includes ABO groups, Rh groups
- Glycolipids act as antigens, causing an immune response
- Blood contains antibodies reacting against foreign antigens ➡ agglutination of RBC or release of haemoglobin, clogging kidney tubules causing renal failure
10
Q
Rhesus effects on newborns
A
- Rh+ will not make anti-Rh antibodies
- Rh- will make anti-Rh antibodies
- Rh+ can receive both Rh+ and Rh-
- Rh- can only receive Rh-
- Incompatibility between mother and fetus leads to severe anaemia
11
Q
Describe the features of neutrophils
A
- A granulocyte
- Most abundant WBC
- Named polymorphonuclear leukocytes
- Phagocytose engulf bacteria
- Serete antimicrobial chemicals
Kill bacteria
12
Q
Describe the features of eosinophils
A
- A granulocyte
- Numbers increase during parasitic infections or allergies
Kill parasitic worms
13
Q
Describe the features of basophils
A
- A granulocyte
- Secrete histamine (a vasodilator) to increase blood flow to tissues
- Secrete heparin (an anticoagulant) to promote mobility of other WBCs by preventing blood clotting
- Overall: attract WBC to inflammation sites
14
Q
Describe the features of monocytes
A
- An agranulocyte
- The largest WBC
- Leaves blood, transforms into phagocytic macrophages that function in infections
- Brain: Microglia
- Lungs: Alveolar macrophages
- Liver: Kupffer cells
15
Q
Describe the features of lymphocytes
A
- An agranulocyte
- The smallest WBC
- Fight viruses and tumors
- Give rise to plasma cells
- Specific immune response
- E.g. Natural killer cells, B cells, T cells
16
Q
Describe the features of platelets
A
- Fragments of bone marrow cells called megakaryocytes
- Maintains haemostasis
- Secretes vasoconstrictors → vascular spasm
- Sticks together, forming platelet plugs
- Initiates formation of clot-dissolving enzymes
- Secretes chemicals attracting neutrophils and monocytes to inflammation sites
17
Q
Describe thrombopoiesis (process of platelet production)
A
- Occurs in the bone marrow
- Produced from haematopoietic stem cells, influenced by thrombopoietin (produced in the liver and kidneys)
- Precursor: megakaryocytes
- 25%-40% of platelets stored in the spleen
18
Q
Describe the role of platelets in haemostasis (prevents excessive blood loss)
A
- release serotonin, acts as vasoconstrictors (narrow blood vessels) to reduce blood loss
- adhere to the blood vessel wall to form a platelet plug, seals breaks
- release clotting factors that convert fibrinogen to fibrin
- platelet-derived growth factor (PDGF) stimulates production of new tissue to replace damaged tissue
- secrete factor XII, forming plasmin to digest fibrin and dissolve the old clot
19
Q
Blood disorders
A
- Anaemia: RBC deficiency
- Haemophilia: Hereditary disorder causing abnormally slow blood clotting
- Septicaemia: bacterial infection, may cause septic shock
- Infectious mononucleosis: infection of B lymphocytes with Epstein Barr virus
20
Q
What is sickle cell disease?
A
- Heredity haemoglobin defect
- Defective haemoglobin turns to gel at low O2 levels
- RBCs elongate and stiffen → blocks circulation → severe pain/organ failure/stroke
21
Q
Pulmonary VS Systemic circuit
A
- Pulmonary: carries blood to the lungs for gas exchange, then returns to heart
- Systemic: supplies blood to the organs including lungs and the heart wall
22
Q
Describe the pulmonary circuit
A
- Carries blood to lungs for gas exchange then returns to heart
- Supplied by right side of heart
- Receives deoxygenated blood from body → pumped into pulmonary artery → into the lungs
- Oxygenated blood returned to the left side of the heart thru pulmonary veins
23
Q
Describe the systemic circuit
A
- Supplies blood to organs
- Supplied by left side of heart
- Aorta delivers oxygen to organs
- Deoxygenated blood returned to right side of heart thru superior/inferior vena cava
24
Q
Describe the pericardium
A
- Double-walled sac enclosing the heart
- Outer fibrous layer
- Inner serous layer
- Outer parietal layer
- Inner visceral layer: adheres to heart surface to form the epicardium
-
Pericardial cavity: space between parietal and visceral layers
- Contains pericardial fluid to lubricate and prevent friction
25
Q
Describe the features of the atrium
A
- Superior chambers
- Thin-walled
- Receive blood returning to heart via veins, pump blood into ventricles
- Auricle: ear-like extension to increase volume
- Separated by interatrial septum
26
Q
Describe the features of the ventricles
A
- Inferior chambers
- Ejects blood into the arteries
- Trabeculae carneae: internal ridges to prevent heart walls from sticking tgt when contracting
- Separated by interventricular septum
27
Q
What are the sulci?
A
- Grooves that mark the boundaries of the four chambers
- Filled with fat and coronary blood vessels
28
Q
Describe the pathway of blood flow through the heart
A
Blood returning from systemic circuit
- Arrives RA via superior/inferior vena cava
- Flow thru tricuspid valve into RV
- RV contracts, eject blood thru pulmonary valve into pulmonary artery
Blood returning from lungs
- Arrives LA via pulmonary veins
- Flow thru bicuspid valve into LV
- LV contracts, eject blood thru aortic valve into aorta
29
Q
Describe the coronary circulation
A
- Supplies oxygen and nutrients to cardiomyocytes
- Left coronary artery
- Anterior interventricular branch
- Circumflex branch
- Right coronary artery
- Supplies RA and SA node
- Right marginal branch
- Small branch to AV node
- Large posterior interventricular branch
30
Q
What happens when blood supply to the myocardium is obstructed?
A
Necrosis: death of body tissue
31
Q
Describe coronary artery disease
A
- Narrowing leading to insufficient blood flow to the myocardium
- Cause: Atherosclerosis (fatty deposits on arterial wall)
- Consequence: Myocardial infarction (arteries blocked → sudden death of cardiac muscle deprived of its blood flow)
32
Q
Describe the components of the cardiac conducting system
A
- SA node: pacemaker cells initiate heartbeat and determine heart rate
- AV node: electrical gateway to ventricles
- AV bundle: signals leave AV node, branch into left and right bundle branches
- Purkinje fibres: distribute electrical excitation to ventricle myocytes
33
Q
Describe the structure of cardiac muscle
A
- Striated
-
Cardiomyocytes
- short, thick
- branched ends: contacts other cells → forms network
- single, central nucleus (surrounded by glycogen)
34
Q
Describe the nerve supply of the heart
A
- Does NOT activate heartbeat
- ONLY modifies rate and contraction strength
- Sympathetic: increase heart rate
- Parasympathetic: decrease heart rate
35
Q
What is the vasa vasorum?
A
Network of microvessels to supply nutrition, oxygen, and waste removal to blood vessles
36
Q
What are aneurysms?
A
- Weak point in an artery or in the heart wall
- Forms thin-walled sac that can rupture
- Cause: combination of atherosclerosis and hypertension
- Common sites: abdominal aorta, renal arteries, arterial circle (brain)
37
Q
Describe the classification of arteries
A
- According to size
-
Conducting
- Largest e.g. aorta, pulmonary trunk
- Expands during systole, recoils during diastole
-
Distributing
- Smaller branches
- Distribute blood to specific organs e.g. renal arteries
-
Resistance
- Small arteries with narrow diameters e.g. arterioles
38
Q
What are arterial sense organs?
A
- Sensory receptors that monitor blood pressure and chemistry
- Transmit to the brainstem to regulate heartbeat, vasomotion, respiration
-
Carotid sinuses
- baroreceptors respond to changes in pressure
-
Carotid bodies
- chemoreceptors monitor changes in blood composition to stabilize blood pH, CO2, O2 levels
-
Aortic bodies
- chemoreceptors
39
Q
Describe the features of capillaries
A
- Exchange vessels
- Endothelium and basal lamina for support
- Thin-walled
40
Q
Describe the classification of capillaries
A
-
Continuous capillaries
- Found in most tissues and organs
-
Fenestrated capillaries
- Filtration pores that penetrate endothelial lining
- Rapid passage of small molecules
-
Sinusoids
- irregular blood-filled spaces
- wide gaps
- allows entry of albumin, clotting factors, proteins from the liver
41
Q
Describe the classification of veins from smallest to largest
A
-
Postcapillary venules
- Receive blood from capillaries
- Muscular venules
-
Medium veins
- Radial and ulnar veins
-
Venous sinuses
- Coronary sinus of heart
-
Large veins
- Vena cava, pulmonary veins
42
Q
Describe the circulatory pathway and its variations
A
- Blood from heart - to arteries - to capillaries
to venules to veins to heart - Exceptions
- Hepatic portal system: Blood flows between two capillary beds
-
Anastomosis: Two veins or
arteries merge without intervening capillaries - Eg Arteriovenous anastomosis: blood flows from artery directly into vein (fingers, palm)
- Eg Arterial anastomosis: two arteries merge
- Eg Venous anastomoses: one vein empties directly into another
43
Q
Describe the aorta and its branches
A
- All systemic arteries arise from the aorta
-
The Ascending aorta
- Coronary arteries
-
The Aorta arch
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
-
The Descending aorta
- Descends thru thoracic and abdominal cavities
- Thoracic aorta: above the diaphragm
- Abdominal aorta: below the diaphragm
44
Q
What is the skeletal muscle pump?
A
- Mainly in medium veins in the limbs
- Presence of venous valves toward the heart
- Prevent the blood from backflow when muscles relax
- Varicose veins: Caused by failure of the valves
45
Q
What are the arteries of the head and neck?
A
- Right and left common carotid arteries
- Vertebral arteries (right and left subclavian artery)
- Thyrocervical trunks (right and left subclavian artery)
- The costocervical trunk (right and left subclavian artery)
46
Q
Continuation of the common carotid arteries
A
External carotid artery
* Superior thyroid artery – to the thyroid gland and larynx
* Lingual artery – To the tongue
* Facial artery – to the skin and muscles of face
* Occipital artery – Posterior scalp
* Maxillary artery – Teeth, maxilla, oral cavity and external ear
* Superficial temporal artery – Chewing muscles, nasal cavity, lateral aspect of face, scalp, dura mater surround brain etc.
Internal carotid artery
* Ophthalmic artery - Orbits, nose and forehead
* Anterior cerebral artery - Medial aspect of cerebral hemisphere
* Middle cerebral artery – Lateral region of temporal and parietal lobes
47
Q
Continuation of the vertebral arteries
A
- Arise from subclavian arteries
- Small branches to supply spinal cord and neck structures
- Enter cranial cavity via foramen magnum, merge to
form basilar artery - Basilar artery branches to supply cerebellum, pons, and inner ear
- Basilar divides at pons-midbrain junction flow into
cerebral arterial circle
48
Q
What is the cerebral arterial circle?
A
- Blood supply to the brain
- Surrounds the pituitary gland and optic chiasm
- Receives blood from internal carotid and basilar arteries
- Two posterior cerebral arteries
- Two anterior cerebral arteries
- A single anterior communicating artery
- Two posterior communicating arteries
49
Q
What happens after blood circulates in the brain?
A
- Blood circulates in brain → collects in Dural Venous Sinuses
- Blood filled spaces between layers of
dura mater - 13 dural Venous sinuses in total
