Evolution
Open circulatory system
Insects
arthropods
No difference between blood and interstitial fluid = hemolymph
Gas exchange: rate of transfer proportional to surface area.
Evolution
Fish: 1 atria 1 ventricle
Heart to gills, gills to body
Water is dense with little O2 per volume
Gills: countercurrent exchange
Gas exchange (blood flows one way while outside water going in opposite direction)
Thermo regulation
kidney
Insects: system of tracheal tubes, gas exchange throughout
Amphibians: 3 chambered heart
Reptiles: double circulation
Pulmonary circuit + systemic circulation
NO mixing of oxygenated and deox blood
Rate of diffusion proportional to surface area
Protists: occurs over entire surface (cnid. Flats)
Earthworms and amphibs: across moist skin
Gills: warmer, saltier less O2
Insects: tracheal tubes: branch out to do exchange with all body parts. Open circ. System NOT involved in transport: O2 CO2
Lungs
Reptiles
Birds
Mammals
Lungs not in contact with all cells of body
Gap bridged by circulatory system
Pharynx: food and air, epiglottis
Larynx: vocal cords (air only)
Trachea: cartilage rings
Bronchi: 2. Right is more horizontal. More stuff
Bronchioles
Alveoli: air sacs and capillaries. 1 cell thick
Breathing
Diaphragm: negative pressure
Tidal volume: air in and out with reg breath
Residual volume: air that remains in alveoli and tubes after you breath out.
Us: air travels down 1 way street.
Birds: better: are travels through… no dead ends
Lungs: only site of gas exchange: need circulatory system
Breath: negative pressure breathing
Partial pressure: gas diffuses from its own high partial press. To low (press. Just this 1 gas contributes to the press. Of air (a mix))
O2 does NOT dissolve easily in blood
Need HEMOGLOBIN to hold the O2
Bohr shift: increase affinity for heme to O2 when pH is elevated (by high CO2)
Myoglobin: protein that binds and stores O2 in muscles
Blood
Blood:
Connective tissue with liquid matrix
plasma and 3 types cells
Leukocytes, erythrocytes, platelets
5L
Kidney maintains plasma (90% water)
All blood cells from pluripotent cells in bone marrow
Disease
Blood pressure: 2 factors:
Cardiac output and peripheral resistance
Atherosclerosis:
Plaques/ hardening of arteries (cholesterol, LDL)
Hypertension: over time, elasticity of vessels
Heart attack: MI, coronary arteries
Stroke: blocked vessel
Control blood flow to capillaries:
Pre-capillary sphincter
Smooth muscle: constrict blood flow to that cap.
Lymphatic system: lymph drained out of circulating blood. Same
Lymph nodes: lots of WBC
Pathway of blood • Right atria (deox blood)
• Right ventricle
• Pulmonary artery
• Lungs : pulmonary circulation
• Pulmonary vein
• Left atria
• Left ventricle
• Aorta: systemic circulation
Atria: thinner walls
Ventricles: stronger
Valves: heart sounds are the closing of valves
2 AV (atria to ventricle)
2 semilunar. From ventricle out of heart
Pulmonary artery and veins : ONLY Time and artery carries deox and a vein carries oxygenated blood
heart
Gap junctions: form communication
SA NODE: local control of rate. Special tissue in right atria
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