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