b3.2 (transport) Flashcards
watch a video on single vs double circulatory systems
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the heart pumps high pressure blood out into the _______ and receives low pressure blood back in via ______
arteries
veins
name the order of blood vessels moving from the left ventricle to the left atrium x7
aorta
arteries
arterioles
capillaries
venules
veins
vena cava
how are arteries adapted to their function of carrying blood away from the heart under high pressure? x3
thick wall with a large amount of elastic fibers and smooth muscle
narrow lumen (maintain high blood pressure and high velocity of blood flow)
no valves
define lumen
the hollow passageway through which blood flows
what purpose does the smooth muscle around the artery serve?
can contract and relax to adjust diameter of the artery lumen, regulating blood flow and blood pressure in the vessel
(KWD vasodilation/constriction)
what are elastic fibers? where are they concentrated (& why)?
bands of specialized proteins called elastin within the extracellular matrix of the tunica media (middle layer of blood vessel walls)
highest in the large, elastic arteries closest to the heart (allows artery wall to expand/recoil with each pulse of blood from the heart, propelling the blood towards the capillaries)
what is the tunica media?
the middle layer of blood vessel walls
what is collagen?
a fibrous protein within the extracellular matrix of the tunica externa (the outer layer of the blood vessel wall) of artery walls
functions of collagen in relation to arteries x4
provide tensile strength (the ability to withstand pressure before breaking when stretched or pulled). (allows the artery to withstand high and variable pressure without bulging (aneurysm) or rupturing)
maintain shape of the artery vessel
anchor arteries to nearby tissues
provide some elasticity for recoil of the artery wall
define tensile strength
the ability to withstand pressure before breaking when stretched or pulled
where can the carotid and radial arteries be found to measure heart rate?
carotid (neck)
radial (wrist)
digital tools for measuring pulse rate often rely on what? how does this work?
optical sensors
a detector on the device detects the amount of light that passes back through the tissue. the volume of blood in the tissue changes with each heartbeat, which alters the amount of light absorbed
factors affecting pulse rate x6
age: pulse rate generally decreases with age
exercise: pulse rate increases during physical activity
stress: emotional stress can elevate pulse rate
medications: medications can either raise or lower pulse rate
temperature: pulse rate increases in higher temperatures
health conditions: heart disease and arrhythmias can cause abnormal pulse rates
the pace of heart rate is set by what cells? where?
pacemaker cells in the right atrium
structures of veins x3
thin wall with small amount of elastic fibers and smooth muscle
wide lumen
valves
to identify arteries and veins in a micrograph, look for the thickness of the walls and the shape/size of the lumen
how does an artery differ from a vein?
arteries have thicker wall and a smaller, more rounded lumen
veins have a thinner wall and a larger, more variable (flatter) shaped lumen
function of coronary arteries
carries oxygenated blood to the heart (cardiac tissue specifically)
how can a heart attack occur in relation to coronary arteries?
a person may develop a build up of cholesterol and other substances in the lumen of the coronary artery called plaque
this restricts ability to bring oxygen to the heart, causing a heart attack
define occlusion
the disruption of blood flow caused by plaque
watch a video on the mammalian heart & movements within it
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what is the cardiac cycle?
a sequence of actions that generate one pump of the heart. depends on heart rate
what does the two halves of the heart do?
_____ half pumps _____ blood to _______ for the purpose of _______
right half pumps deoxygenated blood to lungs for the purpose of being oxygenated
left half pumps oxygenated blood to the rest of the body for the purpose of distribution
what is the coordinated pumping of blood by both halves of the heart controlled by?
sinoatrial (SA) node (specialized cells in right atrium that generate spontaneous electrical impulse)
why is there low pressure in both atria (recieving blood)?
blood has lost its velocity within the body
where do the two atriums receive blood from?
left atrium receives blood from lungs
right atrium receives blood from body
pressure is high in ventricles (blood pumped in from atria). how are walls adapted to this?
walls of ventricle are the thickest part of heart to withstand pressure
where do the two ventricles pump blood to? which is a stronger pumping?
right ventricle pumps to lungs
left ventricle pumps to body
(left is stronger because has to pump into entire body rather than just a nearby organ)
function of atrioventricular valves
prevent back flow of blood back into atria
function of semilunar valves
prevent backflow of blood into ventricles
what is the septum (in heart)?
wall of muscle that separates left and right side of heart
watch a video on control of the cardiac cycle by the SA node (slides 28 to 31 b3.2)
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define systole
contraction of a chamber
define diastole
relaxation of a chamber
4 steps to control of the cardiac cycle by the SA node
initiation of action potential (SA node generates an electrical impulse)
spread of electrical activity (action potential rapidly spreads across both atria, causing them to contract. reaches atrioventricular (AV) node)
delay at AV node (impulse is delayed slightly at the AV node, allowing the atria to fully contract and empty blood into the ventricles)
transmission to vesicles (electrical impulse travels down (the bundle of his, through the left and right bundle branches, and) to the purkinje fibers, causing the ventricles to contract)
what is the function of the atrioventricular (AV) node?
connects the electrical systems of the atria and ventricles
what does an electrocardiogram (ecg) plot?
electrical activity from the SA node and AV node over time
look at a diagram of an ecg plot
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what is the purpose of valves
to ensure blood flow only happens in one direction (towards the heart)
purpose of septum (heart)
separates the heart’s left and right sides, preventing oxygen-rich and oxygen-poor blood from mixing
define lymph
a fluid that circulates throughout the system, carrying immune cells and waste products
define lymph vessels
a network of tubes that transport lymph throughout the body, similar to blood vessels
define lymph nodes
small, bean-shaped structures that filter lymph and house immune cells (like lymphocytes) that help fight infections
spleen functions x3
an organ that
filters blood
removes old red blood cells
stores white blood cells
define thymus
an organ where T-cells (a type of white blood cell) mature
define tonsils
lymphatic tissues located in the throat that help protect against inhaled or ingested pathogens
purpose of the lymphatic system x3
maintain fluid balance
defend against infections
absorb fats
what does high pressure in arterioles enable fluid to do?
pass through arteriole wall cells and into tissue
what does low pressure in venules enable fluid to do?
drain back into capillaries
define transpiration
the process of water evaporation from plant surfaces, primarily through stomata on leaves
define cohesion
water molecules stick together due to hydrogen bonding, creating a continuous column of water in plant vessels (xylem).
define adhesion
water molecules also adhere to the walls of xylem vessels, helping to maintain the column of water
define tension
as water evaporates from stomata, it creates a negative pressure (tension) that pulls more water upwards from the roots through the xylem
how is water able to move from the roots, through the plant, to the leaves?
how does evaporation drive this movement?
the cohesion of water molecules allows the tension to pull the water column continuously
the loss of water through transpiration creates the necessary tension to pull water up
define capillary action
the combined effect of cohesion and adhesion helps to move water through narrow xylem vessels
how are xylem adapted for water transport? x4
Xylem Vessels: Long, hollow tubes: Xylem vessels are continuous and cylindrical, providing a direct and efficient pathway for water transport from roots to leaves.
Lignin in Cell Walls: Strengthens and supports: Lignin provides rigidity to xylem vessels, allowing them to withstand the negative pressure generated during transpiration without collapsing.
Pits in Cell Walls: Water Movement: Pits (small pores) in the xylem allow water to move laterally ensuring a continuous water column across the plant.
Capillary Action: Narrow xylem vessels: The small diameter of xylem vessels, particularly in smaller plants, facilitates capillary action, which assists in the upward movement of water.
how is root pressure (positive pressure that helps move water upwards) generated?
root cells actively absorb water and minerals from the soil, creating an osmotic gradient that draws more water into the roots
how is phloem adapted for movement of sap? x3
Sieve Tubes: Long, tube-like cells with perforated sieve plates for easy flow of sap.
Companion Cells: Support sieve tubes by maintaining metabolic processes and aiding in the loading/unloading of sugars.
Plasmodesmata: Channels connecting cells for coordination of sap movement.
monocot vs dicot:
seed, root, vascular, leaf, flower
monocot:
one cotyledon, fibrous roots, scattered, parallel veins, multiples of 3 (petals)
dicot:
two cotyledon, tap roots, ringed, net-like veins, 4 or 5 petals
structure of dicot stems (vascular bundles) x4 components
(after, look at slide 43 b3.2 for drawing)
arranged in a ring around the stem’s periphery
each vascular bundle contains both xylem & phloem
cambium is located between the xylem and phloem
cortex is located between the vascular bundles and the epidermis
what is the cambium responsible for?
cambium (a layer of meristematic tissue) is responsible for secondary growth (growth in thickness)
what is the cortex responsible for? x2
stores food and helps with structural support
dicot root structure defining feature
vascular tissue is centrally located with xylem in an “X” shape
