Anatomy II exam 1
arterial system function
largest vessels carrying blood away from heart. Elastic walls to withstand the high pressures produced during ventricular systole
What two chambers are stimulated immediately after the SA node depolarizes?
left and right atrium
During systole, the aortic valve is
opened and a large volume of blood flows the aorta and large arteries
factors that determine diffusion in the lungs
partial pressure gradient, solubility, membrane thickness, surface area
Hematocrit
percentage of blood volume occupied by red blood cells
Heart is surrounded by
pericardial sac (pericardium)
How many chambers does the heart have?
4 (2 atria, 2 ventricles)
Hemoglobin structure
4 subunits of oxygen
contractile cells of myocardium
99% of myocardial cells, produce contractions that propel blood
Ventilation: Inspiration
Inspiration (breathing in) → Rib cage up and out= more volume → Abdomen out because diaphragm contracts when thoracic pressure is lower than atmospheric pressure
cardiac output (CO)
Amount of blood pumped in 1 minute (~5 L)
CO2 + H20=
H+
What carries 99% of our O2
Hemoglobin
What causes O2 to bind to hemoglobin
High pressure PO2
Warmer body temperature
Higher O2 saturation takes
Small change in CO2
Increase in ventilation (need to get rid of CO2)
Large change in O2
Increase in ventilation (to get rid of CO2)
End Diastolic Volume (EDV)
Volume of blood in the ventricles at the end of diastole ("preload"), right before contraction
pulmonary circuit
carries blood to the lungs for gas exchange and returns it to the heart
Hemoglobin does what?
carries oxygen in the blood, which oxygen then breaks off of hemoglobin once its been carried to tissues or places that it is needed.
arteries
carry blood away from the heart (arterial)
external respiration
exchange of gases, O2 moves from the lung to the blood and CO2 moves from the blood to the lung.
respiratory zone
includes the alveoli, the only place where gas exchange takes place in the respiratory system
positive inotropic agents
increase contractility
2 main components of blood
plasma (55%) and formed elements (45%)
pleural lining of lungs
visceral pleurae
blood flow
volume of blood flowing through vessel, organ, or entire circulation in given period. determined by blood pressure.
Plasma is mostly what?
water
interstitial fluid contains
water, nutrients, hormones, gases, and wastes and small proteins
Plasma
water, proteins, nutrients, electrolytes, hormones
pulmonary ventilations
breathing (air moving in and out of lung)
isovolumetric contraction
(#4 relaxation) refers to the short period during ventricular systole when the ventricles are completely closed chambers. All 4 valves are closed
cardiac output can be increased by
- increase in end-diastolic volume (preload) - increase in contractility - increase in sympathetic nerve stimulation - increase in heart rate
Local control of blood flow
-The primary mechanism utilized for matching blood flow to the metabolic needs of a tissue -Exerted through the direct action of local metabolites on arteriolar resistance
primary functions of the respiratory system
-intake of oxygen, provide O2 to active tissue -removal of carbon dioxide -exchange of gases and ventilation
autorythmic cells of myocardium
-pacemaker cells -non-contractile cells -self-excitable -can generate spontaneous action potentials triggering the contraction of the heart
SA node (sinoatrial node)
-pacemaker of the heart -sets the heartbeat rate -located in the right atrium -causes atria to contract
airways of lower respiratory tract
1 trunk (trachea) breaks into 2 primary bronchi, breaks into 3 lobes( right) and 2 lobes (left)
pressure changes during cardiac cycle
1. Ventricles begin contraction, pressure rises, and AV valves close (lub); isovolumetric contraction 2. Pressure builds, semilunar valves open, and blood is ejected into arteries. 3. Pressure in ventricles falls; semilunar valves close (dub); isovolumetric relaxation 4. Dicrotic notch - slight inflection in pressure during isovolumetric relaxation 5. Pressure in ventricles falls below that of atria, and AV valve opens. Ventricles fill. 6. Atria contract, sending last of blood to ventricles
cardiac cycle
A complete heartbeat consisting of contraction and relaxation of both atria and both ventricles. (a complete heart beat)
After the AV node depolarizes, which structures conduct the impulse to the myocardium of the ventricles?
AV bundle
veins
At the distal end of capillary beds, blood drains into the venules Venules have larger diameter than capillaries Blood flows from many small venules to larger veins Veins have thinner walls than arteries Less muscular Veins collapse when empty Expand easily and can hold more blood than arteries
intercalated discs
Attachment sites between the transverse lines between cardiac muscle cells, provide strength and prevent adjoining cells from pulling apart when the heart contracts
similarities between cardiac and skeletal muscle
Both have T-tubules & sarcoplasmic reticulum (SR) that release Ca++ when stimulated Both have actin and myosin that interact to create force production Both shorten by 'sliding filament theory'
Carbonic anhydrase reaction
CO2 + H2O <-> H2CO3 <-> H+ + HCO3- (bicarbonate)
Solubility of CO2 vs O2
CO2 is 20x more soluble than O2, causing it to need less of a pressure gradient to diffuse. Even though O2 has a larger pressure gradient than CO2, they still exchange the same amount of gas.
somatic motor nerves
Carry stimulus to the respiratory muscles
systemic circuit
Circuit of blood that carries blood between the heart and the rest of the body.
AV node (atrioventricular node)
Conduction relay node between the atria and ventricles. Signal from the SA node travels through the AV node to the ventricles
CO2 transport in blood
Dissolved in plasma (10%) because it's more soluble then O2 Bound to Hb (20%) makes binding of O2 even harder Bicarbonate (70%) higher CO2 the higher the bicarbonate
internal respiration
Exchange of gases between cells of the body and the blood. O2 moves from blood to the tissues and CO2 moves from the tissue to the blood
Ventilation: Expiration
Expiration (breathing out) → Rib cage down and in → Abdomen in and diaphragm is pushed up- relaxation when thoracic pressure is greater than atmospheric pressure.
What causes dissociation in hemoglobin (O2 breaking off)
Low pressure PO2 (weakens the bond)
function of pleural Membrane
Lubricates the lungs so it doesn't stick to the ribs has slightly adhesive quality that helps pull the lungs outward during inhalation serves as a division between other organs in the body, which prevents them from interfering with lung function.
pericardium
Membrane surrounding the heart, holds heart in place
Capillaries function
Microscopic vessel through which exchanges take place between the blood and cells of the body (tissue)
Neural and hormonal influences on vasoconstriction and vasodilation
Neural= sympathetic (flight or fight) detects stress or exercise which leads to vasoconstriction. Parasympathetic= rest and digest causes vasodilation AKA relaxation. Hormonal= epinephrine and norepinephrine are released due to stress or exercise and cause vasoconstriction
ventricular filling
Phase of the cardiac cycle in which the ventricles expand, their pressure drops, and the AV valves open and blood flows into the ventricles (#5, causes atrial contraction)
peripheral chemoreceptors
Receptors in the carotid arteries and the aorta that monitor blood pH to help regulate ventilation rate. (detect change in O2 or CO2)
central chemoreceptors
Receptors in the central nervous system (medulla) that detect pH changes and provide feedback to medulla to increase the rate and depth of breathing
thermal receptors (thermoreceptors)
Sensory receptors that detect changes in temperature
voluntary control of respiration
Strong emotions can stimulate respiratory centers in hypothalamus Emotional stress can activate sympathetic or parasympathetic division of ANS Causing bronchodilation or bronchoconstriction Anticipation of strenuous exercise can increase respiratory rate and cardiac output by sympathetic stimulation
Higher pressure 46 PCO2 in tissues then in
The lungs ( lower 40 PCO2) where we expire it
Contractility of the heart
The strength of contraction of the heart at any given end-diastolic volume ("preload")
stroke volume
The volume of blood pumped from a ventricle of the heart in one beat
end systolic volume
The volume of blood remaining in the ventricle after ejection (systole).
metabolic local control of blood flow
Tissues regulate their own blood flow proportional to activity level Need for blood to a tissue is indicated when metabolites in the tissue increase With an increase in metabolites, vasodilation takes place When blood flow increases, metabolites are carried away, vessels return to 'normal' diameter
cardiac conduction system
a system of specialized muscle tissues that conducts electrical impulses that stimulate the heart to beat. Contraction comes from within. The heart does not require outside nerves to stimulate contraction.
Charles' Law
as air is warmed when in conducting zone of the airways, warmed gas increase in volume. Warming air helps to expand the lungs.
Boyle's Law (inverse relationship)
as pressure increases, volume decreases. as pressure decreases, volume increases.
bottom of heart=
apex
neural control
autonomic nervous system Influenced by adrenergic receptors of blood vessels (alpha or beta2) Negative feedback loops Receptors baroreceptors, peripheral chemoreceptors, mechanoreceptors Control center (cardiovascular control center) Effector (blood vessels, specifically arterioles) Sympathetic nerves will stimulate constriction of arterioles in most tissues Some exceptions
blood flow in arteries moves
away from the heart
top of heart =
base
Blood flow is regulated by
blood pressure gradient and resistance to blood flow
if flow and resistance go up...
blood pressure with increase. Vice versa
voluntary control
capable of being consciously controlled
exercise increases heart rate (HR) and stroke volume (SV) to increase....
cardiac output
blood pressure is determined by
cardiac output and peripheral resistance due to constriction of arterioles. systolic and diastolic bp
CO=HRxSV
cardiac output equation
cardiac vs skeletal muscle
cardiac: involuntary (the heart does not require outside nerves to stimulate contraction.) skeletal: voluntary
modification by inotropic agents is likely due to...
changes in Ca++ to the myocardium
Chemoreceptors
chemical sensors in the brain and blood vessels that identify changing levels of oxygen and carbon dioxide
During diastole, the aortic valve is
closed and decreases the size of the container which maintains the pressure for blood flow
ventilation is stimulated or inhibited by
conscious thought movement of skeletal muscles chemical changes in bodily fluids (PCO2 & H+)
systole vs diastole
contraction vs relaxation
pre-capillary sphincters function
control blood flow through capillary, at any given time, 3/4 of capillaries in the body may be closed because there is not enough blood to fill all the capillaries at once
negative inotropic agents
decrease contractility
during inspiration pressure in the thoracic cavity
decreases (high to low)
Mechano-receptors
detect pressure, exercise
vasodilatation
diameter of a vessel increases as blood pressure decreases
a-VO2 difference
difference in oxygen content of aterial and venous blood (O2 content in arteries v. Veins)
Sympathetic and parasympathetic nerves
dilate and constrict bronchioles
Purkinje fibers
fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract. looks like webbing
atrial contraction
fills the ventricles
Blood pressure (BP) =
flow (Q) x resistance (TPR)
interstitial fluid
fluid in the spaces between cells. bathes nearly all of the cells in the body
stretch receptors
found in the smooth muscles of bronchi and bronchioles, and in the visceral pleura; respond to inflation of the lungs
partial pressure gradient
gradient: The larger the gradient the more and faster diffusion takes place. partial pressure: the contribution each gas in a mixture of gases makes to the total pressure
blood flow in the veins moves towards the
heart
the frequency of the cardiac cycle is known as the
heart rate
what makes blood 'red'
hemoglobin (iron)
smaller container
higher pressure
Any increase in arterial blood pressure may ________ afterload and therefore ________ stroke volume
increase, decrease
during expiration pressure in the thoracic cavity
increases
endocardium
inner lining of the heart
muscles of expiration
internal intercostals and abdominal muscles and diaphragm
⇑ volume of container = ⇓ pressure ⇓ volume of container = ⇑ pressure
inverse relationship of pressure
chronic hypertension
is when arterial BP is elevated, which causes injury/weakness to the inner wall of the blood vessels
Bigger container
lower pressure
exercise stimulates these receptors
mechanoreceptors and chemoreceptors
Lower pH in blood
more acidic metabolites and CO2, which weakens the O2 bonds to break of hemoglobin
pulmonary ventilation
movement of air into and out of the lungs. VE=BR X TV air/min= # breath/ min x air/ breath
capillary exchange
movement of substances between blood and interstitial fluid. Fluid movement takes place primarily by osmosis and filtration pressure.
Myocardium
muscular, middle layer of the heart that contracts and pumps
external control blood flow
neural, hormonal
respiratory pump
pressure changes during breathing move blood toward heart by squeezing abdominal veins as thoracic veins expand
Blood flows through the heart and through the vessels as a result of
pressure gradients. INVERSE RELATIONSHIP between pressure and volume
Vasomotion=constriction and dilation
primarily takes place in the arterioles
Respiration 3 phases
pulmonary ventilations external respiration Internal respiration
2 ventricles (inferior)
pumping chambers, blood fills the ventricles from the atria. pumps blood to arteries
skeletal muscle pump
pumping effect of contracting skeletal muscles on blood flow through underlying vessels
Systole
pushes blood out of heart
2 atria (superior)
receiving chambers, blood fills the atria returning from outside the heart
formed elements
red blood cells, white blood cells, platelets
Venoconstriction
reduces volume of blood in reservoirs and allows greater blood volume to flow where needed
Control of Ventilation
respiratory center in brain (medulla) controls ventilation -motor nerves carry stimulus to the respiratory muscles -sympathetic and parasympathetic nerves dilate and constrict bronchioles *NEAR THE CARDIOVASCULAR CENTER IN MEDULLA (many of the same stimuli
Effectors of respiration
respiratory muscles
Hearing-Breuer Reflex (inflation reflex)
respond to excessive inflation of lungs, which then inhibits the I neurons in order to slow down respiratory rate
muscle mechanoreceptors
sensitive to force and speed of muscular movement
muscles of inspiration
sternocleidomastoid, scalenes, external intercostals, diaphragm, pectoralis minor
Afterload
the amount of resistance to ejection of blood from the ventricle
vasoconstriction
the constriction of blood vessels, which increases blood pressure.
The greater the volume of blood, the greater the stretch on the cardiac muscle, & therefore : _______________
the harder the ventricles contract
Dalton's Law
the total pressure of a gas mixture is equal to the sum of the partial pressures of its individual gases. atmospheric air: 79% nitrogen 20% oxygen <1% carbon dioxide
Location of the heart
thoracic cavity
diastole
time where blood fills the heart
Capillaries
tissue- any of the fine branching blood vessels that form a network between the arterioles and venules.
major functions of blood
transport, protection, regulation
Red Blood Cells (RBC)
transports gases (O2 and CO2) between lungs and tissues of the body
pre-capillary sphincters closed
vasoconstriction
Neural and hormonal control stimulate...
vasoconstriction. this increases blood pressure
pre-capillary sphincters open
vasodialation
Veins
venous system, carry blood towards the heart
