The Cardiovascular System Flashcards
1
Q
The Heart
A
- Four chambered structure with two pumps
- Right side pumps deoxygenated blood ( pulmonary circulation)
- Left side pumps oxygenated blood (systemic circulation )
- atria receives from vena cava or pulmonary vein
- Atria contracts their muscles
- Ventricles are more muscular
- Atrioventricular valve: separates atrium and ventricles
- Semilunar valves:
2
Q
Semilunar valves
A
- separates ventricular blood from vessels and atrium
- Prevents back flow
- Types:
- Tricuspid valve: Right atrioventricular (RAT)
- Mitral / bicuspid valve: left atrioventricular (LAB)
- Pulmonary valve: right ventricle from pulmonary
- Aortic valve: left ventricle from aorta
3
Q
Left ventricle is very muscular, but if the right were as muscular,______would occur
A
lung damage
4
Q
Electric conduction of the heart
A
- Impulse pathway travels through the following structures in order: SA node, AV node, AV bundle, the Purkinje fibers.
- SA node generates 60-100 beats per minute
- Once the impulse initiates, both atria contract
- Atria systole: contraction resulting from increased pressure - Signal goes to AV node and waits for ventricle to fill
- Signal then goes from bundle of His and purkinje fiber to ventricular muscle.
- Intercalating discs in the muscles allow for coordinated contractions
- Neurological autonomic input to the heart is important in speeding up and slowing down the rate of contraction, but not generating it in the first place.
- Parasympathetic signals are provided by vagus nerve.
5
Q
Contraction
A
- Two phases to a heart beat
- Systole: ventricular contraction, pressure ↑, “LUB”
- Diastole:ventricles relax and fill with blood, pressure ↓ “DUB” - Elasticity of arteries maintains the diastolic pressure
- Cardiac output of both ventricles: CO = HR x SV
- Normally 5L per min.
6
Q
Types of vessels
A
arteries, veins, and capillaries
7
Q
Function of arteries
A
- Arteries take blood away from heart and towards tissues
8
Q
Order of vascular throughout the body
A
- Arteries → Arterioles → Capillaries → venules → veins
9
Q
Endothelial lining
A
- Release blood clot chemicals
- Release vasodilators and vasoconstrictors
- Allow paracellular movement
10
Q
Arteries
A
- Highly muscular and elastic
- Moves blood away from heart
- Carries oxygenated or deoxygenated blood
11
Q
Capillaries
A
- Small and single layered (endothelium only) vessels
- Diffuses gases, nutrients, Hormones, and waste
12
Q
Veins
A
- Thin walled and inelastic venules
- Veins have low elasticity due to muscle amount
- They contain 3/4 of the body’s blood.
- Venous blood in lower body have high pressure
- Valves prevent back flow
- Broken valves leads to varicose veins(large veins with pooled blood) - No lower extremity movement → blood pooling → increased risk of blood clotting
13
Q
Pathway of blood flow
A
- Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery→ lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → arteries → arterioles → capillaries → venules → veins → venae cavae → right atrium
14
Q
Portal systems ( blood travels through TWO capillary bed before returning to heart)
A
- Hepatic: gut wall to liver
- Hypophyseal: hypothalamus to anterior pituitary
- Renal : glomerulus to nephron
15
Q
Composition of blood
A
- Plasma @ 55% volume
- Cells (erythrocytes, leukocytes, and platelets) 45% volume
- Serum is plasma without clotting factors and fibrinogen.
16
Q
Erythrocyte-Red blood cells
A
- Designed for oxygen transport
- Since oxygen is non polar; not dissolvable in cytoplasm; hemoglobin carries it.
- Benefit of shape: large surface area, easier travel through capillaries, and increase oxygen transport.
- Don’t contain mitochondria and other organelles; no oxygen metabolism, more space for hemoglobin, no cellular division
- A blood count of RBCs gives hematocrit (% RBC in sample) and hemoglobin (# of hemoglobin) measurements.
17
Q
Leukocytes-White blood cells
A
- <1% of volume
- Defender of immune system
- Only cells in blood to contain nuclei
18
Q
5 types of leukocytes
A
- Granulocytes ( toxic granules involved in inflammation, allergies, pus formation
- NEUTROPHIL, EOSINOPHIL, BASOPHIL - Agranulocytes
- Lymphocytes:
- initiates extrinsic pathway to apoptosis.
- Function as specific immune response
- First responders to repeat infections
- sometimes trained by vaccination
- Types based on maturation site
- B -Cell: from bone marrow → Plasma cells
- T-Cell: from thymus → Cytotoxic and helper T cells - monocytes
- Phagocytize pathogens
- in blood they are known as monocytes
- In the organs they are known as macrophages
- i.e Microglia (CNS), Langerhans cell (skin), osteoclasts (bone)
19
Q
Thrombocyte-Platelets
A
- Released form megakaryocytes
- Assist in blood clotting
- Made in bone marrow in process called hematopoiesis; stimulated by thrombopoietin
20
Q
Types of blood antigens
A
- ABO Antigens
- Three alleles are possible (A, B or O)
- A and B are co-dominant; simultaneously expressed.
- Individuals with both are “universal recipients”
- Antibodies for A and B antigens are initially made because E. Coli protein has similar composition.
- O is recessive
- O blood type individuals are “universal donors” because there isn’t an anti-O antibody.
- These proteins determine naming system for blood types
- Matching these proteins between individual is critical for transfusion
- Anti-AB, A or B are IgM; does not cross placenta. - Rh Factor
- First described in Rhesus monkeys
- Individuals either have the antigen (Rh+) or don’t (Rh-)
- Autosomal dominant gene
- Erythroblastosis fetalis stems from this antigen exposure.
- Anti-Rh are IgG
21
Q
Purpose of cardiovascular system
A
Maintain blood pressure, gas, and solute exchange, coagulation, and thermoregulation.
22
Q
Blood Pressure
A
- Speaks on the effectiveness of this system
- It is measured by a sphygmomanometer
- It is expressed as ratio of systolic and diastolic pressures.
- Largest drop in pressure occurs in arterioles due to thinned Walled capillaries
- A pressure gradient across the system ( much like emf during electric resistance) drive cardiac output
- ΔP = CO x TPR
- Arterioles and capillaries resist blood flow due to ↑length and ↓cross-sectional area
23
Q
Blood pressure too low?
A
- Baroreceptors (stimulate vasoconstriction)
- chemoreceptors (senses concentration → ADH secreted → ↑blood volume/ pressure)
- low perfusion to the juxtaglomerular cells ( aldosterone secreted→ ↑sodium conc. → blood pressure.)
24
Q
Blood pressure too high?
A
- Vascular relaxation stimulated
- ANP (diuretic) secreted by atrial cells
25
Gas and Solute exchange
- Facilitated by concentration gradients
26
Oxygen
- Low solubility in plasma
- Carried by hemoglobin within one of its 4 heme subunits
- Measurements
- Arterial partial pressure (70-100 mmHg) (not easy way)
- Oxygen saturation using finger probe ( easy way)
- Its binding and dissociation to hemoglobin happens by cooperative binding that produces sigmoidal curve.
- During exercise : ↑oxygen dissociation from hemoglobin
27
Carbon dioxide
- Low solubility in plasma
- Low affinity to hemoglobin
- Therefore its transported in plasma as Bicarbonate (HCO3)
- CO2 + H2O ⇔ H2CO3 ⇔ H+ HCO3 (Bicarbonate buffer system)
- Carbonic anhydrase catalyzes this reaction
- Causes of right shift (lower affinity) of oxyhemoglobin dissociation curve:
- If ↑CO2 produced → ↓ blood pH / ↑[H+] → protons interfere with Hemoglobin-Oxygen affinity → dissociation curves shift right → ↑oxygen dissociation from hemoglobin
- Increased temperature
- Increased 2,3 BPG (glycolysis)
- Bicarbonate buffer system also link respiratory and renal systems
- Hyperventilation → ↓ [H+] / ↑pH. → kidney secretes HCO3 → ↓pH
28
Nutrients, waste, and Hormones
- After consuming carbs and amino acids → enter blood through hepatic portal system
- After consuming fats → enter blood through thoracic duct.
- Hormones are usually near the organ or transported in plasma
- Entering or exiting tissue occurs mostly by Concentration gradients.
29
Fluid Balance occurs in blood due to pressure gradients
- Hydrostatic pressure
- Generated by heart contractions
- Measure as blood pressure
- Pushes fluid ,against endothelium, from blood into tissue
- Osmotic pressure
- Type of sucking pressure
- Generated by plasma protein
- Pulls fluid from tissue into blood.
- A.K.A oncotic pressure
30
Coagulation
- Clots are composed of coagulation proteins and platelets
- Damaged endothelium → coagulation cascade → prothrombin activation → thrombin → fibrinogen → fibrin
- Coagulation cascade starts by exposure of collagen.
- Prothrombin is activated by thromboplastin to become thrombin
- Thrombin converts fibrinogen to fibrin
- Fibrin aggregates in damaged area
31
where does the greatest drop in blood pressure occur.
Arterioles.
