ch 42 - exam 3 Flashcards
gas exchange and circulation
3 factors that affect diffusion rates?
- area avalable for gas exchange
- thickness of respiratory surface
- partial pressure gradient of gas across respiratory surface
ventilatory organs in water breathers
internal and external gills
countercurrent flow
seen in fish gills, as water flow over lamellae dec. blood flow through lamellae inc., like a loop
concurrent flow
not seen in fish gills, as water flow over lamellae dec blood flow inc. MEET AT 50% numbers add up to 100%
what is negative pressure breathing?
when inhaling, lungs expand and diaphragm moves down, “belly breathing”
what is positive pressure breathing?
when inhaling, lungs contract and diaphragm moves upward, making more pressure in lungs
how much oxygen binds to hemogloben in rbc?
98.5%
how many molecules of O2 can 1 hemoglobin bind to?
up to 4 molecules
what happens with cooperative binding?
large amounts of O2 are delivered to resting and exercising tissues, hb dumps 3/4 of O2, S curve, changes affinity for O2
what happens without cooperative binding?
smaller amounts of O2 delivered to resting and exercising tissues, linear graph, hb would only dump 1/2 of O2
what is the bohr shift?
as pH inc. hb is more likely to unload O2
CO2+H2O–>H2CO3 –> H+ +HCO3-
UNLOADS MORE O2
What happens in lungs?
deoxygenated blood goes to lungs, reverse from bohrs shift and favors loading of O2
how do veins and arteries differ in structure?
veins have thinner walls, low pressure, valves that prevent backflow
arteries have thicker walls and higher pressure, elastic
what are capillaries?
small and extremely thin walled, bp much lower over capillaries, diffusion is slow
How does interstitial fluid form?
- blood enters capillary from arteriole, high bp
- fluid leaves
- fluid returns to capillary
- blood leaves capillary to venule, lower bp
Steps of Pulmonary Circulation
- blood enters right atrium from body via vena cava
- right ventricle
- lungs
- left atrium from lungs
- left ventricle
- blood is pumped to body
What do intercalated disks do?
in cardiac muscle tissue, help electric signals move quickly and seamlessly via gap junctions
5 steps of electrical activation of the heart
- signal originates at SA node
- signal spreads over atria
- signal delayed at AV node
- signal spreads
- ventricles relax
How do we regulate circulation?
- arterioles: smooth muscle, contractions/relacations control blood flow to regions
- nervous system and hormones
- baroreceptors: pressure hormones, heart/major arteries, detects the stretch of heart muscles
what are the main parts of the lungs?
- trachea
- bronchi
- bronchioles
- alveoli
What happens in the lungs in regards to hb? equation?
- any CO2 in blood diffuses into alveoli/air
- hemoglobin loads O2, 100% O2
- CO2+H2O<-H2CO3<-H+ +HCO3-
- reversal of Bohr shift
What happens in tissues in regards to hb? equation?
- tissue has low O2 (b/c used to do respiration)
- hemoglobin unloads O2
- CO2+H2O->H2CO3->H+ +HCO3-
What are the 4 chambers of the heart?
- right atrium
- right ventricle
- left atrium
- left ventricle
what are the 4 valves in the heart?
- tricuspid valve
- Right AV valve
- semilunar valve
- pulmonary valve
