Circulation Flashcards
Circulation system 5 functions
Respiratory gas transport
Nutrient transport
Nitrogenous waste transport
Hormone transport
Heat transport
Circ system is required in…
Animals larger than a certain size
Animals with more minimal oxygen demands (high metabolism)
Circ system consists of…
Pumping mechanism (e.g. heart)
Plumbing (arteries and veins)
Surfaces for diffusion (capillaries)
Two basic designs of circ system
Open vs. Closed circulatory systems
Open circulatory system
Hemocoel
Interstitial space
Blood flows from arteries into diffuse spaces between cells (interstitial space) or into special blood cavities surrounding organs then returns to the heart via ostia
Blood in open systems is called hemolymph
Hemocoel is the body cavity of an open circulatory organism
Closed circulatory system
Blood confined to vessels at all times
Materials pass into and out of blood via diffusion
Artery vs Vein
Carries blood away from heart artery
Carries blood to heart vein
Veins are thinner walled,
less elastic,
have much less smooth muscle,
and are of larger diameter
Makeup of plumbing for circ system
Artery -> arteriole -> capillary -> venule -> vein
Arterioles
Small arteries made up primarily of smooth muscle
Circular smooth muscle can contract, reduce blood flow to particular organs
Serves as a control mechanism to divert blood to where it is most needed
Pressure of blood when it reaches veins
By the time blood reaches veins, pressure has decreased to zero
How does blood return to the heart?
Skeletal muscle surrounding veins applies pressure when those muscles contract
One way valves direct blood anteriorly, restrict flow posteriorly
Differences between vertebrate circulatory patterns is related to:
Location of respiratory organs
Structure of Heart
Amphibian circulatory system
Double circuit
Pulmonary/Systemic
Two atria, single ventricle
Both oxygen-rich and oxygen poor blood travel through the ventricle
Trabeculae prevents oxygenated and deoxygenated blood from mixing to any great extent
Bird-mammal circulatory systems
atria/ventricle relation?
circulation?
Complete separation between atria and ventricles
Double Circulation - complete separation between pulmonary and systemic circuits
Portal system
which 3?
Connects two capillary beds
Hepatic portal system
Renal portal system
Hypophyseal portal system (connect hypothalamus to anterior pituitary)
Blood supplies to heart
Left ventricle -> aorta -> coronary arteries (left/right) -> coronary veins (left/right) -> coronary sinus -> right atrium
CAD
death?
what builds up?
what do plaques do?
what does restricted blood flow do?
solutions?
Leading cause of death, killing 370,000 anually
Fat, cholesterol, and other substances collect in the artery walls
Plaques damage artery walls and block blood flow
Severe buildup of plaques lead to restricted blood flow in the muscle and then a heart attack
stent or bypass
Hepatic portal system
what does it collect from?
where does that stuff go?
what does the stuff contain?
Where do those things go after the liver?
Collects venous blood from digestive tract and spleen
Delivers blood to the liver via the hepatic portal vein
portal blood contains the substances absorbed by the digestive tract
substances are processed in the liver before being either … released into hepatic veins, or store in the liver for later use
Placenta
O2 and nutrients come from mother via the placental interface
Fetal wastes are passed in blood to mother via placenta
Fetal circulation
Placenta -> umbilical vein -> ductus venosus -> inferior vena cava -> right atrium -> foramen ovale -> left atrium -> left ventricle -> aorta -> systemic body circulation
Function of lungs in the fetus
Not functional, and some blood passes through the pulmonary trunk, which bypasses to the aorta via the ductus arteriosus
Ductus venosus does what?
carries oxygenated blood and bypasses the liver, dumping oxygenated blood into the inferior vena cava
Heartbeat
systole?
diastole?
contraction
Relaxation
Blood movement from atria to ventricles
Blood movement from ventricles to the body
atrial systole/diastole
step 1 and 2
Step 1 : systole pushes blood from atria to ventricle
Step 2 : diastole creates negative pressure in atria and draws blood in from the venous system
Ventricular systole/diastole
step 1 and 2
Step 1: Diastole creates negative pressure in the ventricle and allows for blood to be drawn in
Step 2: Systole of the ventricles provides force to move blood through the circulatory system
Cardiac muscle unique quality?
automaticity
Pacemaker cells
location? function?
SA Node
initiate wave of electrical activity, which stimulates contraction of cardiac muscle
Fish circulatory system
Deoxygenated blood -> heart -> ventral aorta -> aortic arches (through gills) -> dorsal aorta -> rest of body
Wave of electrical activity in heart
SA node ->
both atria ->
AV node ->
AV bundles ->
purkinje fibers->
both ventricles
Heart rate control?
what two nerves control heart rate?
slow/fast?
Where do the nerves terminate?
Vasomotor control center in medulla regulates HR
Vagus nerve (cranial) / Accelerator nerve (spinal nerve)
Vagus slows / Accelerators speed up
They terminate in the SA node
Baroreceptor
2 locations ?
A receptor which detects changes in blood pressure
Aortic arch and carotid artery
What influences heart rate?
BP, O2 and CO2 concentration, blood pH, hormones, emotional state
BP too high?
BP too low?
Vagus nerve slows down heart rate
Accelerator nerves speeds up heart rate
Parasympathetic vs Sympathetic
Para slows down, Sympa speeds up
Chemoreceptors monitor what?
O2, CO2, pH of blood
Chemoreceptors and baroreceptors communicate with what?
Vasomotor control center
Capillary exchange
in closed circ systems?
Is it just diffusion?
materials (O2, nutrients, hormones) move to
Capillary <–> interstitial fluid <–> body’s cells
and what can be sent back to systemic circulation is other materials (CO2, N wastes, hormones)
No
Blood composition of vertebrates
Is plasma cellular?
55% plasma (acellular) (water, solutes, gases)
45% cells RBCs, WBCs, Clotting factors (erythrocytes, leukocytes, platelets/thrombocytes)
Capillaries are permeable to?
Impermeable to?
water, nutrients, small ions, gases
large plasma proteins
Hydrostatic pressure / Osmotic pressure relationship
Do they oppose each other?
If hydrostatic pressure is greater than osmotic pressure, net movement favors going out of the capillary
If osmotic pressure is greater than hydrostatic pressure, net movement favors going into the capillary
They oppose each other
Where is hydrostatic pressure greatest?
What impact does this have?
At the proximal end of the capillary because blood is under higher pressure moving from a big vessel to a small vessel (protein-free)
Forces water and small molecules out
Important for providing tissue cells with oxygen and nutrients
Where is colloidal osmotic pressure greatest?
What impact does this have?
Highest at distal end of the capillary because blood is more concentrated than the interstitial fluid, drawing water and dissolved molecules (wastes) into the capillary
Proximal end can be thought of as what?
Arterial (carrying nutrients in) vs Venous (carrying wastes out)
Mechanisms for regulating blood flow
Contraction of smooth muscle arterioles - reduces blood flow to particular body organs
Contraction of precapillary sphincters - controls flow through particular parts of a capillary bed
Fish heart
Zig Zag like a S
Top right of S is sinus venosus
Left arch of S is atrium
Bottom right arch of S is ventricle
S terminates at left is conus arteriorsus
Frog heart 6 major structures
Spiral valve - separates oxygen and deoxygenated blood streams (much like septum)
pulmocutaneous artery - carries blood to lungs (pulmonary veins backflow to heart)
Carotid artery - carries blood to head
Systemic artery - carries blood to trunk
trabeculae - keep O2/De-O2 blood separated pretty well
Branchia
gills
What happens when outflow exceeds inflow?
Describe what causes this?
Excess fluid, lymph, from the interstitial space is collected by the lymphatic system
More hydrostatic pressure than there is osmotic colloidal pressure forces out more than colloidal osmotic pressure brings in, causing a buildup of fluid
Lymph returns to the circulatory system where?
The thoracic duct, draining into the left innominate vein of the neck
What are major fluid compartments of an animal’s body? How does blood fit into this picture?
Blood vessels, interstitial, and intracellular. Blood exists in the blood vessels of the body, so it would fit into the blood vessels section.
What are the advantages of an open vs a closed circulatory system?
An open system would be advantageous because it would require less energy to operate since pressure does not need to be maintained as rigorously with a plumbing network, rather it would just need to organize the arterial system it has well.
What is the main difference between the pattern of blood flow in a fish and a mammal or a bird?
The main difference in blood flow between a fish and a mammal/bird is the single circuit vs double circuit system. Fishes still send blood to a respiratory organ, but there is only one pump powering both, which makes it not as effective a pump as a mammal or bird. However, the fish pump requires less energy since it is only powering 1 pump rather than 2.
Describe the pattern of blood flow through the mammalian heart, noting which chambers contain oxygenated/deoxygenated blood
Right atrium (de) -> Right ventricle (de) -> Pulmonary trunk (de) -> Pulmonary artery (de) -> Pulmonary veins (ox) -> Left atrium (ox) -> Left ventricle (ox) -> Aorta
Describe the role of hemoglobin and other respiratory pigments in oxygen transport in the blood
Hemoglobin binds oxygen to it and transports it to cells in the body.
How is that hemoglobin can take up oxygen in lung capillaries, but release it in tissue capillaries
Hemoglobin binds in low oxygen settings, so in tissues that need oxygen because not a lot is readily available, hemoglobin will release this oxygen into the plasma, the oxygen will diffuse over the blood vessel into the interstitial fluid, and enter the cell that needs it via diffusion.
