11 Cardiovascular System Flashcards
Cardiovascular system made of
Heart and blood vessels
Closed system
Function of cardiovascular system
Transport O2
Nutrients
Cell wastes
Hormones to and from
Size and weight of heart
Size of fist
Weighs less than a pound
Location of heart
Thoracic cavity, between lungs, in inferior mediastinum
Apex (pointed tip) is directed toward
Left hip and rests on diaphragm
Between junction of 4th and 5th ribs
Base of heart points toward
Right shoulder
At level of 3rd coastal cartilage
Pericardium parts
Fibrous pericardium-loose and superficial
Serous membrane
Parts of serous heart membrane
Parietal pericardium
Visceral pericardium
Parietal pericardium
Outside layer
Lines inner surface of fibrous pericardium
Visceral pericardium
Next to heart; aka epicardium
Pericardial cavity
Space between layers of pericardium. Filled with serous fluid
Fluid helps reduce friction during beating
Layers of the heart wall
- Epicardium
- Myocardium
- Endocardium
Epicardium
Outside layer; the visceral pericardium
Myocardium
Middle layer
Mostly cardiac muscle (only in heart)
Endocardium
Inner layer aka endothelium
Four chamber of heart
Atria (right and left)
Ventricles (right and left)
Atria
TOP (attic)
1.Receiving blood chambers (from system or lungs)
2.Assist with filling ventricles
3. Blood enters under low pressure
Ventricles
- Discharging chambers
- Thick-walled pumps of heart. (Thicker on left)
- During contraction, blood is propelled into circulation
Superior vena cava drains
Structures above diaphragm low on O2
Inferior vena cava drains
Structures below diaphragm low on O2
Tricuspid valve
Under right atrial chamber where used blood pools.
Blood must pass through to get to right ventricle
Try to make sure it fits righy
Which ventricle has thicker myocardium?
Left ventricle.
Left ventricle does more work
Interatrial septum
Separates two atria longitudinally (right and left)
Interventricular septum
Separates two ventricles longitudinally (right and left)
Function of right atrium
Receive blood from vena cava
Function of right ventricle
Discharge deoxygenated blood into lungs
Left atrium function
Oxygen rich blood flows through pulmonary veins into left atrium
Left ventricle function
Discharging chamber
Pumps oxygenated blood to body
Heart functions as double pump because
Arteries carry blood away from heart
Veins carry blood toward the heart
Pulmonary circuit pump
Right side
Pumps into lungs
Systemic circuit pump
Left side
Pumps into entire system
Explain pulmonary circulation
- Blood flows from right side of heart, to lungs, to left side of heart
- Blood pumped out of right side, through pulmonary trunk, which splits into pulmonary arteries, takes oxygen poor blood to lungs
- Oxygen rich blood returns to the heart from the lungs via pulmonary veins
Systemic circuit
- Oxygen rich blood returned to left side of heart. Pumped out into the aorta
- Blood circulates to systemic arteries and to all body tissues .
- Oxygen poor blood returns to right atrium via systemic veins
Systemic veins empty blood into superior or inferior vena cava
Heart valves flow
Only let blood flow in one direction to prevent backflow
Atrioventricular valves
Between atria and ventricles
Bicuspid (mitrial) and tricuspid
Left AV valve
Bicuspid (mitrial)
Right AV valve
Tricuspid valve
Semilunar valves
Between ventricle and artery
Pulmonary semilunar valve
Aortic semilunar valve
Pulmonary semilunar valve
Between right ventricle and pulmonary trunk
Aortic semilunar valve
Between left ventricle and aorta
Valves open and close in response to
Pressure changes in the heart
Responsible for pumping of blood
Semilunar valve movement
Closed during heart relaxation
Open during ventricular contraction
AV valve movement
Open during heart relaxation, when blood passively fills chambers.
Closed during ventricular contraction
What anchors AV valves?
Anchors cusps in place by chordae tendinae to the walls of ventricles
Made by series of cusps
AV valves
Blood in the heart chambers does not
Nourish myocardium
The heart has its own nourishing circulatory system made of
Coronary arteries
Cardiac veins
Coronary sinus
Coronary arteries
Branch from aorta to supply heart muscle with oxygenated blood
Cardiac veins
Drain myocardium of blood
Coronary sinus
Large vein on the posterior of heart
Receives blood from cardiac veins
Blood empties from heart muscle into the right atrium via
The coronary sinus
Blood re-enters circulation this way
Intrinsic conduction system
Cardiac contractions happen independently from nerve impulses
Regular & continous contractions
BPM of atrial cells
60
BPM of ventricular cells
20 to 40
Unifying control system of the heart
Intrinsic conduction system
Nodal system
Intrinsic conduction system
Which systems regulate heart activity?
Autonomic nervous system (sympathetic: fight or flight )
(Parasympathetic: slow down heart rate)
Intrinsic conduction system
What does the nodal system do?
- Sets, heart rhythm
- Heart muscle depolarization in one direction (atria to ventricles).
- Enforces heart rate of 75 BPM
Noodle system is made of
Special nervous tissue independent of nervous system
Components of intrinsic conduction system
- Sinoatrial node
- Atrioventricular node
- Atrioventricular bundle
- Purkinje fibers
SAAP
Sinoatrial (SA) node
In right atrium
Serves as heart’s pacemaker
Starts each heartbeat
Atrioventricular (AV) node
- At junction of atria and ventricles
3.Causes atria to contract
3.Impulse delayed briefly
Atrioventricular (AV) bundle, bundle of His and bundle branches are in
Interventricular septum
Purkinje fibers
Spread within the ventricle wall muscles
Supply myocardium with contraction impulses
After impulse travels through these blood is ejected from the heart
Tachycardia
Rapid heart rate over 100 BPM
Bradychardia
Slow heart rate, less than 60 BPM
Cardiac cycle
One complete heartbeat
Both atria and ventricles contract and relax
Normally around 0.8 seconds for a complete cycle
Systole
Contraction
Diastole
Relaxation
Average heart rate
75 BPM
Ventricular filling aka
Atrial diastole
Atrial diastole
1.Heart is relaxed
2. Low heart pressure
3. Open AV valves
4. Blood flows into atria and ventricles
5. Semilunar valves are closed
Atrial systole
Ventricles remain in diastole (relaxed)
- Atrial contract
- Blood forced into ventricles to complete ventricular filling
Isovolumetric contraction
- Atrial systole ends; ventricular systole begins
- Intraventricular pressure rises
3.AV valves close - For a moment, ventricles are completely closed chambers
Ventricular systole (ejection phase)
- Ventricles continue contracting
- Intraventricular pressure now surpasses pressure in major arteries leaving heart. (Blood forced from ventricles into arteries)
- Semilunar valves open (because of increased pressure)
4.Blood ejected from ventricles
- Atria relaxed and filling with blood
Isovolumetric relaxation
1.Ventricular diastole begins
2. Pressure falls below that in major arteries
3. Semilunar valves close
4. For another moment, ventricles are completely closed chambers
5. When atrial pressure increases above intraventricular pressure, the AV valves open
Lub
Longer, louder heart sound caused by the closing of the AV valves
Dup
Short, sharp heart sound caused by the closing of semilunar valves at the end of ventricular systole
Cardiac cycle steps
- Atrial diastole (ventricular filling)
- Atrial systole
3.Isovolumetric contraction - Ventricular systole (ejection phase)
- Isovolumetric relaxation
Cardiac output
Amount of blood pumped by each side ventricle of the heart in one minute
Stroke volume
Volume of blood pumped by each ventricle in one contraction (heartbeat)
Normal stroke volume
70 ml pumped out left ventricle with each heartbeat
Cardiac output formula
CO=HR(heart rate)(75 beats/min)xSV(stroke volume) (70 ml/beat)
CONVERT TO LITERS (L/min)
What percentage of blood in ventricles is pumped with each heartbeat
60%
What is the critical Factor controlling stroke volume
How much cardiac muscle is stretched
Starling’s law of the heart
The more cardiac muscle is stretched,
The stronger the contraction
More blood volume=stronger contraction
Important factor influencing the stretch of the heart muscle
Venous return
High blood return, more stretching
Factors modifying basic heart rate
- Neural (ANS) controls
- Hormones and ions
- Physical factors
- Neural ANS controls
Sympathetic speeds heart rate
Parasympathetic slows heartrate
Hormones and ions role in heartbeat regulation
1.Epinephrine and thyroxine speed heart rate
2.Excess or lack of calcium, Na, and K ions also modify heart activity
Physical factors
Age, gender, excercise, body temp influence heart rate
Vessels that carry blood away from the heart
Arteries and arterioles
Vessels that play a role in exchanges between tissues and blood
Capillary beds
Vessels that return blood toward the heart
Venules and veins
Tunics of blood vessels except capillaries
- Tunica intima
- Tunica media
3.Tunica externa
Tunics in capillaries
Tunica intima
Tunica intima
Friction reducing lining
Endothelium
In contact with blood
Tunica media
Smooth muscle and elastic tissue
Controlled by sympathetic nervous system
Tunica externa
Protective outermost covering
Mostly fibrous connective tissue
Supports and protects the vessel
Artery is thicker than vein because
Tunica media is much thicker because they help help blood to many tissues
Artery vs vein physical differences
Thicker tunica media in artery
Veins have valves
Veins and arteries communicate through
Capillaries
Aterioles
Branches of larger arteries, get thinner, form network with venules
Venules
Branches of veins
Capillary beds
Network of thin vessels where arteries meet veins
Capillaries are one cell layer thick
Capillaries let
Gases and substances pass through (waste products, nutrients)
To withstand changes in pressure, arteries have
Stronger, stretchier tunica media
Why do veins have a thinner tunica media?
They operate under low pressure
Why do veins have valves?
Prevent backflow of blood
Lumen of veins is larger than
That of arteries
Skeletal muscle “milks” blood in veins towards
Heart
Capillaries
One cell layer thick
Exchanges between blood and tissue
Capillary bed parts
Vascular shunt
True capillaries
Microcirculation
Blood flow through capillary beds
True capillaries
Branch off a terminal arteriole
Empty into post capillary venule
Precapillary sphincter
Guards entrance to capillary beds
When sphincters are closed blood flows through
Vascular shunt.
From terminal arteriole to post capillary venule
Aorta
Largest artery in the body
Leaves from left ventricle of the heart
Ascending Aorta
Leaves left ventricle
Aortic arch
Arches to left
Thoracic aorta
Travels downward through thorax
Abdominal aorta
Passes through diaphragm into abdominopelvic cavity
Arterial branches of the ascending aorta
Right and left coronary arteries serve the heart O2 rich blood
Brachiocephalic trunk splits into the
Right common carotid artery (supplies head)
Right subclavian artery (behind clavicle)
Left common carotid artery splits into the
Left internal and external carotid arteries
Left subclavian artery branches into the
Vertebral artery
In axilla,
Subclavian artery becomes axillary artery-> brachial artery-> radial and ulnar arteries
Arterial branches of thoracic aorta
Intercoastal arteries supply muscles of thorax wall
Other branches supply lungs
Esophagus
Diaphragm
Bronchial arteries
Lungs
Esophageal arteries
Esophagus
Diaphragm
Phrenic arteries
First branch of abdominal aorta
Celiac trunk
Three branches of celiac trunk
Left gastric artery
Splenic artery
Common hepatic artery (liver)
Superior mesentric artery
Supplies most small intestine
Supplies first half of large intestine
Left and right renal arteries
Supply kidneys
Left and right gonadal arteries
Ovarian and testicular arteries
Lumbar arteries
Serve muscles of abdomen and trunk
Inferior mesenteric artery
Serves second half of large intestine
Left and right common iliac arteries
Final branches of aorta
Internal iliac arteries serve the
Pelvic organs
External iliac arteries
Enter thigh-> femoral artery -> popliteal artery -> anterior and posterior tibial arteries
Which veins drain into the superior vena cava?
- Radial and ulnar veins-> brachial vein -> axillary vein
- Cephalic vein
- Basilic vein drains
- Basilic and cephalic veins are
- Subclavian vein
- Vertebral vein
- Internal jugular vein
Basilic and cephalic veins join at
joined at median cubital vein (elbow area)
Basilic vein drains
medial aspect of arm and empties into brachial vein
Cephalic vein drains
drains lateral aspect of arm and empties into axillary vein
Subclavian vein receives
Blood from arm via axillary vein
Blood from skin and muscles via external jugular vein
Vertebral vein drains
Posterior part of head
Internal jugular vein drains
Dural sinuses of the brain
Left and right brachiocephalic veins receive blood from
Subclavian veins
Vertebral veins
Internal jugular veins
Brachiocephalic veins join to form the
Superior vena cava -> Right atrium of heart
Azygos vein drains the
Thorax
Anterior and posterior tibial and fibial veins drain the
Legs
Posterior tibial vein turns into
Popliteal vein
Femoral vein
External iliac vein
Great saphenous veins
Longest veins of the body
Receive superficial drainage of the legs
Each common iliac vein is formed by
Union of internal and external iliac veins
Right Gonadal vein drains into
Right ovary in females
Right testicle in males
Left gonadal vein empties into
Left renal vein
Left and right renal veins drain
The kidneys
Hepatic portal vein drains
The digestive organs.
Travels through liver before it enters systemic circulation
Left and right hepatic veins drain the
Liver
Arteries that supply most of the cerebrum
Anterior & middle cerebral arteries
Internal carotid arteries divide into
Anterior and middle cerebral arteries
Vertebral arteries join once within the skull to form
Basilar artery
Basilar artery serves
Brain stem and cerebellum
Posterior cerebral arteries form from the
Division of the basilar artery
Posterior cerebral arteries supply
Posterior cerebrum
What unites anterior and posterior blood supplies?
Small communicating arterial branches
Circle of Willis or cerebral arterial circle
Complete circle of connecting blood vessels
Hepatic portal circulation is made by
Veins draining into digestive organs
Which then empty into hepatic portal vein
Hepatic portal vein drains
Digestive organs
Spleen
Pancreas
Carries blood to liver where it is processed before returning to systemic circulation
Hepatic portal vein
What is absorbed in the first capillary bed?
Nutrients and toxins
What happens in the second capillary bed?
Nutrients and toxins leave
Arterial pulse
Expansion and recoil of blood vessel wall that occurs as the heart beats
Average healthy pulse at rest 70 to 76
Force that causes blood to continue flow
Blood pressure
Force against inner walls of vessels
What happens when ventricles contract?
Blood forced into elastic arteries close to heart (Pulmonary arteries, pulmonary trunk, aorta)
Blood flows in descending pressure gradient
What happens to pressure in blood vessels as distance from heart increases?
Pressure decreases
Explain pressure in different kinds of blood vessels
Pressure is highest in arteries
Lower in capillaries
Lowest in veins
Pressure in arteries at peak of ventricular contraction
Systolic
Pressure when ventricles relax
Diastolic
Indirect method of measuring systemic arterial blood pressure most often in brachial artery
Auscultatory method
Blood pressure formula
BP= CO (cardiac output) x PR (peripheral resistance)
Peripheral resistance PR
Friction of blood as it passed through vessels
Cardiac output CO
Amount of blood pumped out left ventricle per minute
Neural factors on blood pressure
Parasympathetic nervous system has little to no effect on BP
Sympathetic nervous system
Promotes Vasoconstriction (narrowing of vessels), which increases blood pressure
Kidneys regulate blood pressure by
Altering blood volume
If blood pressure is too high, the kidneys
Release water in the urine
If blood pressure is too low, what do kidneys do?
Release renin to trigger formation of angiotensin II, a Vasoconstrictor
Angiotensin II stimulates release of aldosterone which?
Enhances sodium and water reabsorption by the kidneys
Effect of temperature on blood pressure
Heat vasodilates
Cold vasoconstricts
effect of chemicals on blood pressure
Epinephrine increases heart rate and blood pressure
How does diet affect blood pressure?
Low salt
Low saturated fats
Low cholesterol
Prevents hypertension
Causes of increased arterial blood pressure
Decreased blood volume
Exercise
Postural changes
Increased blood viscosity
chemicals
Normal Systolic pressure ranges
110 to 140
Normal diastolic pressure ranges
70 to 80 mmHg
How to identify hypotension?
1.Systolic below 100
2.Associated with illness
3.Warning sign of circulatory shock
How to identify hypertension?
Sustained arterial pressure of 140/90 or higher
Warns of increased peripheral resistance
Can damage body and blood vessels
Exchange through capillary walls happens because
Concentration gradients
Oxygen and nutrients leave blood and move into tissues
CO2 and other wastes exit tissue cells and enter blood
Routes that substances take entering or leaving blood
- Direct diffusion through membranes
2 Diffusion through intercellular clefts - Diffusion through pores of fenestrated capillaries
- Transport via vesicles
Gaps between cells in capillary walls
Intercellular clefts
Fluid movement in and out of capillary depends on
Difference between two pressures
Role of blood pressure at capillary beds
Forces fluid and solutes out of capillaries
Role of osmotic pressure in capillaries
Draws fluid into capillaries
Blood pressure is higher than osmotic pressure at the
Arterial end of capillary bed
Fluid moves out of the capillary at the beginning of the bed and
Is reclaimed at the opposite venule end
When do vessels have a net fluid movement out?
When blood pressure is greater than osmotic pressure
When do vessels have a net fluid movement in?
When blood pressure is lower than osmotic pressure
