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
Describe the **systemic** circuit
* 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
Describe the **pericardium**
* *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
Describe the features of the **atrium**
* *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
Describe the features of the **ventricles**
* *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
What are the **sulci**?
* Grooves that mark the boundaries of the four chambers
* Filled with fat and coronary blood vessels
28
Describe the pathway of blood flow through the heart
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
Describe the **coronary circulation**
* 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
What happens when blood supply to the **myocardium** is obstructed?
**Necrosis**: death of body tissue
31
Describe **coronary artery disease**
* 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
Describe the components of the **cardiac conducting system**
* **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
Describe the *structure* of **cardiac muscle**
* Striated
* **Cardiomyocytes**
* short, thick
* branched ends: contacts other cells → forms network
* single, central nucleus (surrounded by *glycogen*)
34
Describe the *nerve supply* of the heart
* Does NOT activate heartbeat
* ONLY modifies **rate** and **contraction strength**
* Sympathetic: increase heart rate
* Parasympathetic: decrease heart rate
35
What is the **vasa vasorum**?
Network of *microvessels* to supply nutrition, oxygen, and waste removal to blood vessles
36
What are **aneurysms**?
* 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
Describe the *classification* of **arteries**
* 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
What are **arterial sense organs**?
* 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
Describe the features of **capillaries**
* Exchange vessels
* Endothelium and basal lamina for support
* Thin-walled
40
Describe the *classification* of **capillaries**
* **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
Describe the *classification* of **veins** from smallest to largest
* **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
Describe the circulatory pathway and its variations
* 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
Describe the aorta and its branches
* 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
What is the skeletal muscle pump?
* 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
What are the arteries of the head and neck?
* 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
Continuation of the common carotid arteries
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
Continuation of the vertebral arteries
* 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
What is the cerebral arterial circle?
* 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
What happens after blood circulates in the brain?
* Blood circulates in brain → collects in **Dural Venous Sinuses**
* Blood filled spaces between layers of
dura mater
* 13 dural Venous sinuses in total
