Midterm learning outcomes Flashcards
Fish circulation: how does their circuit and spongy myocardium limit exercise capacity
the heart isnt well oxygenated, some fish have changed to a compact myocardium if they have higher metabolic needs
how can an incompeltely divided heart be an advantage fir lung breathing animals that routinely stop ventilating for long periods
it allows blood to bypass lungs during diving, hibernation etc. and it saves energy
compare and contrast open vs closed systems using molluscs as ex
Molluscs have open system: heart or contractile organ, some blood vessels
Squid/octopus has closed: 2 branchial hearts and 1 systemic heart, gills
explain how blood flow return to the heart in an open system
drains into cavity and gradually returns to heart
explain how insects can function with seperated circulatory and respiratory systems
respiration occurs through diffusion of oxygen through sides of body, insect circulation is only for hormone and nutrient transport
is a high pressure system better or not
No superior system because they can make up for things in other ways, same rate of oxygen delivery
Explain how gas exchange relies on a combination of ventilation and circulation
relies on bulk flow: moving medium over resp surfaces, where gasses disolve and the transport of gases in the circ system
Use simple physics (fick equation, boyles law) to understand the structure of respiratory systems
Boyles law: P1V1 = P2V2 so increase of volume then pressure decreases (opening chamber allows for things to flow in, moves down pressure system)
Fick equation: Q = DA(P1-P2)/L better rate of diffusion (Q) with more surface area, small path length
adaptations for maximizing gas exchange
- increase surface area (ex. external gills)
- maximizing partial pressure gradients (passive ventilation, active ventilation: nondirectional, tidal, unidirectional (concurrent, counter current, crosscurrent))
- minimizing path length (less thickness = less distance = more diffusion) high energetic needs = less thickness
General features of spider respiration
- book lungs
- cavity opens via spiracle, air diffuses in spiracle, gasses cross lamellae into hemolymph
- some have tracheal system
General features of insect respiration
- gas exchange surface close to all cells
- extensive tracheal system throughout whole body
- breathe through spiracle
- taenidia to prevent collapse
General features of fish respiration
- use buccal opercular pump
- use gills with thing filaments (lamellae)
- operculum helps move water across gills
-counter current flow (perpendicular to blood) - some use ram ventilation
General features of sea star respiration
- skin gills/external gills
- countercurrent
- papulae (projections on exoskeleton)
- cilia move fluids one way outside and other way on inside
General features of bird respiration
- adapted for high metabolic demands
- 2 lungs
- 9 air sacs
- 2 breath cycle
- unidirectional - cross current flow
- rigid lungs, highly vascularized
General features of mammal respiration
- lungs have conducting airways and respiratory airways
- two alveolar cells and capillaries
- lungs contain stale air, never fully emptied
-inspiration active, exhalation passive
compare and contrast concurrent, countercurrent and crosscurrent in animals
- birds use cross current
- sea star, fish uses counter current
the role of surfactants and the pleural sac
- pleural sac: surrounds each lung, two layers of cells with small space between (pleural cavity) contains pleural fluid
- surfactants: reduces surface tension by disrupting hydrogen bonds between water molecules, produced by type II alveolar cells
how breathing is regulated and relates to organism homeostasis
- automatic rhythmic process
- chemoreceptors modify output
- central and peripheral chemoreceptors
- sensors and effectors + response helps homeostasis if O2 levels drop/ Co2 too high
Why the evolution of bulk flow was necessary for larger animals
Diffusion is only effective over short distances so large animals had to develop another way for gas exchange
components of a circulatory system (3)
Heart, blood vessels , blood
Properties of blood
- primarily water with dissolved ions, hemocytes, dissolved proteins
- may have respiratory pigments (inverebrates)
- carrier proteins and blood clotting proteins (vertebrates)
- vertebrate blood: plasma, RBC, other blood cells
- RBC: most abundant, round/oval, biconcave, hemoglobin, lack nucleus etc
the relationship between tissues within blood vessels and their function
- tunica intima: endothelial cells
-tunica media: smooth muscle cells, vasoconstriction/dilation - tunica externa: support
the fluid column effect on blood pressure
- blood pressure above heart is less
- below heart is more
Poiseuilles equation in the context of blood flow
- resistance is inversely proportional to vessel radius to the 4th power
- if radius is halved: resistance increases by factor of 16, flow rate decreases to 1/16 its former value
How the structure of capillaries aids in fluid exchange
- has fenestrae (pores)
- hydrostatic pressure pushes fluid from blood to interstitial fluid
- osmotic pressure pushes water from interstitial space into capillaries
the starling landis hypothesis
Pressure through the system is going to go from high pressure to low pressure at the venous end, osmotic pressure is relatively static
the purpose and network of the lymphatic system
- excess extracellular fluid is returned to the bloodstream by lymphatic system
- lymph nodes remove pathogens from lymph
why the pulmonary circuit is a low pressure system
to avoid fluid loss from capillaries so the lungs dont flood
how autoregulation and intrinsic and extrinsic factors act on arterioles to regulate blood flow
-autoregulation: prevents excessive flow of blood into tissue
- intrinsic: smooth muscle in arterioles sensitive to extracellular fluid, metabolites alter vasoconstriction/dilation, paracrine signals
- extrinsic: sympathetic NS maintains vasomotor tone, vasoconstriction/dilation in muscles- blood directed away from organs in flight or fight
3 types of animal pumps
contractile chamber, skeletal muscle, pulsating blood vessels
mammalian heart structure, contraction, cardiac output
- systole diastole
- pacemaker in SA node right atrium
differences in heart structure across taxa
-fish: serial chambers, passive valves
- amphibian: two atria one ventricle, spiral fold seperates blood
- turtles/lizards/snakes: two atria and ventricle with cavum venosum, cavum pulmonale and cavum arteriosum
-mammals: compact, two atria two ventricles, myogenic
action potentials in heart
-pacemaker potential: caused by slow influx of Na, via F channel, increase in Ca depolarizes, decrease in Ca to stop it, increase in K for repolarization
- cardiomyocyte waveform: influx of Na depolarizes, decrease in Na increase in K to stop it, decrease in K increase in Ca to plateau, decrease in Ca increase in K to repolarize
neurohormonal modulators of heart contraction
-Adrenergic = increased HR, more contraction, sympathetic
- cholinergic = reduce heart rate, less contraction, parasympathetic
Describe features of molecules present within the plasma membrane
- lipids: phospholipids, glycolipids and sterols
- protein: integral & peripheral
- carbohydrates: glycolipids and glycoproteins
Identify the function of membrane proteins
- channel: simple diffusion, always open
- transporter: moves molecules across membrane, opens on one end, out the other
- enzyme: catalyzes chemical reaction
- receptor: binds with molecules & then intitiates change
- structural protein: attaches to other molecules, anchor
describe the mechanisms by which different molecules pass through plasma membrane
- lipid soluble: passive diffusion
- Hydrophilic molecules? need active transport/ facilitated diffusion
describe the relationship between concentration gradients and electrical gradients
concentration gradients give rise to electrical gradients
