Circulation and gas exchange

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

Our system

4 chambered heart

Double circulation:

Right side: pulmonary

Left side: systemic

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

Controls of breathing

Pons

Medulla

Sensors in aorta

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

homeostasis

If low O2

kidneys: erythropoietin: increase production of erythrocytes

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

Arteries: higher pressure. From heart

Veins: pressure from move skeletal muscle.

Vocabulary

Systole

Diastole

SA node