bio unit 4 Flashcards
what do we require from the enviroment
nutrients and oxygen
how is the rate of diffusion o oxygen and nutrients limied and what is the solution
it is limited by distance
- cardiovascular system for transoport of substances through the body
- transported by flow of blood through circulatory system
- bulk flow rather than diffusion
what are the materials transported from the external environment to tissues
nutreints, water, gases (especially o2)
between tissues of body
wastes, nutrients, hormones
from tissues to external environment
metabolic wasted, gases (especially CO2), heat
what is the cardiovascular system with components
series of tubes (blood vessels) filled with fluid (blood) and connected to a pump (heart)
what is he pericardium
it is part of the external anatomy of the heart, a tough membranous sac surroiing the heart, made up of epicardiu and parietal layer of pericardium with a small amount of fluid between them that acts as a lubricant
what are coranary atary
part of the external anatoy of the heart
- nourisht he heart muscle with blood
what does the heart demand for
oxygen and this depends on adequete blood flow , if lacks then leads to hear attack (myocardial infraction)
what is the left atrium
part of the internal anotome, recieves oxyginated blood from the pulmonary veis and sends to left ventricle
what is the left ventricle
receives oxygenared blood from left atrium and sends to body, after going through body retuns back to the heart via superior vena cava (this cycle is called the systemic circuit)
right atrium
recieves deoxygiinated blodd from venae cavea and sends to right ventricle
right ventricle
recieves deoxygentated blood from the right atrieum and sends to lungs ( via pulmonary trunk)
what are valves and what are the two types of valves
ensure flow is unidirectional
Atriovetnriular valves (tricuspid and bicuspid)
semilunar valves (Aortic and pulmonary)
what is atrioventricular valves and what holds them
tricuspid and bicuspid
atached on ventrucular side to collagenous cord(chordinae tendineae (prevent valves from bieng pushed back into the atrium)
what is semulunar valves and what holds them
Aortic and pulmonary
- prevent backflow into ventricles
- the semilunar valves do not need cords to brace them because of thier shape
what are the two divisions of the path of blood flow and describe them
pulmonary circuit, blood vessels in the lungs and those that connect the lunds to the heart
systemic circuit, encompases the rest of the blood vessels in the body
describe the path of the two cardiovascular system divisions
page 92
what does the heart do to blood pressuse
increases it
what are the specialized cells of the heart
they are autorythmic cells (oacemaker cells) need then bc heart don’t get activated by the nervous system
located in sinoatrial node (SA node)
right atrium, near superioir vena cave,
and spontaneously generate action potentials withought input fom the nervous system
what is the membrane potential for pacemaker cells
have an unstable membrane potential that slowly drifts upwards from starting point og -60 mV until reaches threshold and iniates action potential
no resting membrane have special If channels
permeable to K+ and Na+
when membrane potential is negative:
Na+ influx > K+ efflux, net influx of + charge, slow depolarication of membrane
when membrane potential is positive
If channels close, Ca2+ channels open, contiend depolirzation, threshold reached, many Ca2+ channels open and rapid influx of Ca2+, steep depolarization phase of action potential
what happens during repolarization
at the end of depolarizaio the Ca2_ channels close and K+ channels open slowly;efflux of K+ causes repolarization
what is a major difference beween action potentials and pacemaker pottentials in the pacemaker cells
page 93
what modulates the rate of pacemaker potential
autonomic division
explain autnimoc division how heart rate increaases and decreases
page 95
what initiates the electrical excitation of the heart and does it spread
pacemaker/autorythmic cells initiate the electrical excitation of the heart, and speads to neibourgingh cardiac cells via gap juncions in the interalaed discs
explain the events of conduction
page 96
what is the electrocardiogram
it is used to obtain infromation of the heart and heart rate
records the electrical ativity at the surface of the skin using electrodes
measure the voltage differentials occuring diring the cardiac cycle, signle contraction-relaxation of mechanical events
3 leads to make einthoven’s triangle
now 12 ECG leads`
what are the 3 waves of an ECG
P wave - depolarzation of Atria
QRS complex - ventricular depolirazation
T wave - repolirization of ventricles
talk about mechanical events and electrical events
mechanical events lag slightly behind electrical events
what are the 2 segmensts of an ECG
P-R segment, atrial contraction
S-T segment, ventricular contraction, just after Q wave
what is the cardiac cycle
the cardiac cycle is the period from one heart beat to the next and has two phases
- systole - contraction
- diastole - relaxation
explain steps to cycle
page 100
explain the sounds of the heart
lub - due to closing of AV valves
Dub - due to closing of semilunar valves
liquids and gasses flow from….
high pressure to areas of lower preaser
what happens when heart contracts
preassure increases, blood flows out of the heart to lower pressure areas
End distolic volume (EDV)
maximumvolume in venricle - endo of ventricular filling
End systolic volume (ESV)
minimum volume in ventricle, end of ventricular contraction
cardiac output
the amount of blood pumped byy the heart in one minute
= heart ratexstroke volume
stroke volume = EDV-ESV
factors influencing heart rate
- parasympathetic stimulation - decreses heart rate, via vagus nerve, ach
- sympathetic stimulation - increase heart rate, via great cardiac nerve, NE
- plasma epinephrine (from adrenal medulla) - increases heart rate
factors influencing stroke volume
- parasympathetic stimulation - decrease conractililty
- sympathetic stimulation - increases contractility
- plasma epinephrine - increases contractility
- increased end-diastolic volume - increases stroke volume
what is a blood vessels structure
hollow tube made of lumen (central cavity) and wall( made of layers)
what are the walls of blood vessels
inner lining - endothelial celes make up the endothelium
elastic connective tissue
vascular smooth muscle - vasoconstriction (narrowing of vessel), vasodilation ( widening of the vessel)
fibrous connective tissue
what are the types of blood vessels
artery - thick walled to withstand high pressure
arteriole smallest arteries
capillary - smallest blood vessel, exchange of material
venule - smallest veins
vein - transport blood at low pressure
why does blood flow
because of a pressure gradient (deltap) between the arteries (p1-highest) and viens (p2-lowest)
flow is directly proportional to the pressure gradient
explain the factors hat influence blood flow
page 106
wheni is pressure increased or decreased
p inc when volume dec
p dec by friction (occurs beetween blood and walls of the blood vessel
what is friction exerted by a tube
resistance
how does resistance and pressure difference play a role i blood pressure
flow is inversely proportional to resistance
flow is proportional to pressure diff
how is resistance determined
lenghth, radius and viscosity, chanches in radius most important
what is blood presssure and what is the pulse
the driving pressure caused by the heart pumping, highest in arteries and lowest at point of return to the heart
pulse is increase in pressure caused when ventricles contract and push blood into aorta
what are the two parts that make up blood pressure and how do you estimate it
- systolic pressure: time when the heart is contracting - highest arterial pressure
- diastolic pressure: time when the ventricle relaxes - lowest aterial pressure
estimated using sphygmomenomety, cuff and stethescope shi
what is the mean arterial pressure (MAP)
since arterial pressure is pulsatile use a single value to represent driving pressure
MAP = diastolic p +1/3 (systolic P - diastolic P)
what are the factors affecting MAP
cardiac output, changes in blood volume, peripheral resistance
how is regulation of blood presssure
coordinated by CNA - a homeostatic reflex
what does the bararoreceptors do for blood pressure
barororecetors are stretch sensetive mechanoreceptors found in vessel walls of the, corotid artery ( moniters blood pressure to brain) and Aorta (moniters blood pressure to body). and blood pressure is monterded though sensory input from them
explain bararoreceptor reflex
page 109
what is blood
circulating component of extracellular fluid responsible for carrying subsances around the body
what are the 4 major compnents of blood
plasme - fluid portion of the blood
red blood cells - erythocytes
white blood cells - leukocutes
plaelets - thormbocytes
red blood cell
- biconcave in shape
- most ubundant cells in blood
-contain protien haemoglobin - major fnction of erythocytes is gas transport
- humans, RBC’s lack a nucleas and mitochondria so no protien synthesis and no energy produced by oxidative phosphrylation
white blood cells
- lyphocytes
- monocytes
- granulocytes (3 types)
- nuetrophils
-esunophils
-basophils
macrophages and neutrophils are the professional phagocutes in the body
platelets
- involves in blood clotting
- derived from megakaryocytes, pinch off and have no nucleus
why haemoglobin synthesis
required for RBC function to transport oxygen
explain haemoglobin synthesis
page 112
bohr effect
A shift in haemoglobin saturation due to pH
haematopoieis and where are all blood cells produced
blood formation
red bone marrow
what are cells that arise from a single precursor, and what are thier typees
pluripotent hematopitc stem scell, uncommited stemm cells still capble of many fates and progenitor sells are committed to one or two cell types
cytokines
small peptides/protiens secreted by one cell to send signals to another, chooses path for blood formation and splits them by factor
leukposis
formation of leukocytes (white blood cells) that is regulated by the colony-stimulating factors (CSFs)
cytokines released by leukocyts regulate further leukocyte production
colony-stimulating factors(CSFs)
CSFs are released by endothelial cells, morrow fibroblasts and white blood cells
induce cell division and cell maturation in stem cells
thrombopoiesis, how they formed what they contain, when are they active
megakaryocytes are parent cells that produce platelets (thrombocytes)
growth and maturation are regulated by cytokine theombopoietin
platelets no nuclues but contain mitochindria, smooth ER and granules filled with clotting protiens and cytokines
platelets are always present in the blood, but active only when damage has occured to the walls of the circulotory system
megakaryocyte
a polypoid cell with a lobed nuclues, parent cells that produce platelets (thrombocytes)
megakaryocyte resides in the bone marrow and extends is outer edges through the endothelium into blood stream
