A&P II - Cardiovascular (Unit 2) Lecture

Pulmonary Circuit

Blood flow to the heart then to the lungs then back to heart

Systemic Circuit

Blood flow from the heart to the rest of the body

Artery

A blood vessel that carries blood from the heart to other parts of the body

Conducting Arteries

Large, elastic blood vessels that cushions change in blood pressure

Distribution Arteries

Medium-sized, muscular blood vessels that are often on sites of pressure points

Arteriole

Smallest form of an artery, less muscular with a poor tunica externa; connects to capillary

Capillary

Single cell thick, endothelial blood vessels connecting arterioles with venules; site of gas and nutrient exchange; can be turned on/off

Continuous Capillary

Type of blood vessel that allows water and small molecules to diffuse through - larger molecules/cells do not fit. Completely lined & found in all tissues except epithelia and cartilage

Fenestrated Capillary

This porous blood vessel is seen in the choroid plexus and endocrine organs

Sinusoidal Capillary

Tiny blood vessels like fenestrated, but flatter and more irregular. Occurs in liver, bone marrow, spleen, endocrine organs, intestines, & kidneys

Venule

Smallest form of a vein; connects to capillary

Vein

A blood vessel that carries blood back toward the heart to get oxygenated; has valves to prevent back flow

Tunica Interna

Innermost layer of blood vessels; made of endothilum & internal elastic membrane

Tunica Media

Middle layer of blood vessels; consists of smooth muscle and loose connective tissue; thicker in arterties

Tunica Externa

Outermost layer of blood vessels; made of fibrous connective tissue

Vasoconstriction

Decrease in the diameter of blood vessels

Vasodilation

Increase in the diameter of blood vessels

Atrioventricular Valves

2 valves that allow blood into the ventricles; supported by chordae tendinae

Semilunar Valves

2 valves that allow blood to leave the ventricles into the pulmonary artery & aorta

Parietal Pericardium

The tough outermost layer of the pericardium that is attached to the diaphragm and the sternum

Visceral Pericardium

The innermost layer of the pericardium that adheres to the heart

Epicardium

The outer, serous membrane of the heart wall

Myocardium

The middle, muscular layer of the heart wall

Endocardium

The membrane that lines the cavities of the heart and forms part of the heart valves

Right Atrium

Vena Cavae brings blood to the _____ of the heart

Tricuspid Valve; Right Ventricle

After entering the right atrium, blood passes through the _____ on the way to the _____

Pulmonary Semilunar Valve; Pulmonary Trunk

From the right ventricle, blood is pushed through the _____ into the _____

2 Pulmonary Arteries

From the pulmonary trunk, the _____ takes the blood to the lungs

4 Pulmonary Veins; Left Atrium

Now with fresh oxygen, the _____ returns the blood to the heart's _____

Mitral Valve; Left Ventricle

From the left atrium, the blood has to pass through the _____ to go to the _____

Aortic Semilunar Valve; Aorta

From the left ventricle, blood passes the _____ into the _____, where it is delivered throughout the body

Systemic Arteries

The aorta carries blood to the _____

Systemic Capillaries

The systemic arteries carries blood to the _____ where gas and nutrient exchange occurs

Systemic Veins

The _____ finally returns the blood to vena cavae, where it must pass on the way to the heart

Systole

The contraction of the chambers of the heart to drive blood into the aorta and pulmonary artery

Diastole

The widening of the chambers of the heart between two contractions when the chambers fill with blood

60 - 100 bpm

Normal pulse range

Heart Murmur

An abnormal sound of the heart; usually a sign of abnormal function of the heart valves

Specialized Muscle Cells

Cardiac cells (only 1%) that coordinates the heartbeat

Contractile Cells

Cardiac cells (99%) that propel the blood

Sinoatrial node

Initiates the heartbeat from the upper wall of the right atrium, causes atria to contract, natural pacemaker of the heart

Bundle of His (AV Bundle)

Disperses the signal for ventricular contraction into the right and left bundle branches, then on to the apex and then U-turn into the Purkinje fibers

Electrocardiogram (EKG)

Records electrical impulses from the heart

P wave

Atrial depolarization on an EKG

QRS complex

Ventricle depolarization and atrial repolarization on an EKG

T wave

Ventricular repolarization on an EKG

U wave

Thought to represent repolarization of the papillary muscles or Purkinje fibers on an EKG

An action potential to bring Ca++; binding of Ca++ to troponin

Contractile cells need...

Rapid Depolarization

Step 1 of contraction: Fast Na++ Channels open

Plateau

Step 2 of contraction: Na+ channels close and slow Ca++ channels open and balance +/- ions

Repolarization

Step 3 of contraction: Slow K+ channels opens as Ca++ channels close

Atrial systole > atrial diastole > ventricular systole (1st & 2nd) > ventricular diastole (early & late)

Phases of the cardiac cycle

Cardiodynamics

Movement & force during contractions

End-Diastolic Volume (EDV)

The volume of blood that is in the ventricles before the heart contacts

End-Systolic Volume (ESV)

The volume of blood remaining in the ventricles at the end of a contraction

Cardiac Output

Blood pumped from each ventricle per minute

Epinephrine

A hormone that increases heart rate & stroke volume due to stress

Norepinephrine

A hormone than can increase blood pressure - can also increase heart rate and stroke volume

T3 & T4

Thyroid hormones that regulate how your body uses energy - can increase heart rate and stroke volume

Stroke Volume

Difference between the end-diastolic volume and the end-systolic volume (EDV - ESV)

Preload

How much ventricles can stretch during diastole

Contractility

The amount of force during a contraction per the preload; regulated by ANS, hormones & electrolytes level

Afterload

Amount of tension the contracting ventricle produces to open the semilunar valves

Rheumatic Fever

Reaction to strep infection that deteriorates the valves up to 20+ years later

Pericarditis

Inflamed pericardial surfaces due to friction, increases fluid and causes cardiac tamponade

Coronary Artery Disease

Blockage of coronary circulation, may cause ischemia and angina

Bradycardia

Abnormally slow heartbeat

Tachycardia

Abnormally rapid heartbeat

Premature Atrial Contractions (PACs)

"Surprise" atrial contractions caused by stress, caffeine, and drugs

Paroxysmal Atrial Tachycardia (PAT)

Abrupt episodes of rapid atrial contractions, ventricles can keep pace, HR over 180bpm

Atrial Flutter

Atrial impulses <350 per min., not stable, often degenerates into a fibrillation

Atrial Fibrillation

Impulses up to 500 per minute, atria quiver, ventricles do not keep up, can go unnoticed

Premature Ventricular Contractions (PVCs)

"Surprise" ventricular contractions cause by epinephrine, drugs, and ion imbalances

Ventricular Tachycardia

4 or more PVCs without a normal beat

Ventricular Fibrillation

Ventricles quiver due to an uncoordinated contraction, to the point of no longer pumping; can cause cardiac arrest - can be fatal

Mitral Valve Prolapse

Cardiopathy resulting from the mitral valve not regulating the flow of blood between the left atrium and left ventricle of the heart

Myocardial Infarction

Destruction of heart tissue resulting from obstruction of the blood supply to the heart muscle; heart attack

Capillary Bed

A layer of tissue densely packed with capillaries. Blood travels through metarteriole or on to a thoroughfare channel

Arteriole Anastamosis

Collateral arteries merge and creates a direct connection between an arteriole and a venule

Metarteriole

Link between an arteriole and a venule; serves as a vascular shunt when precapillary sphincters are closed

Thoroughfare Channel

Continuation of metarteriole at venule end that enables blood to bypass capillary bed. Lacks smooth muscle

Hydrostatic Pressure

Created by a force pushing a liquid (blood). Pushes from high to low

Blood Pressure

Arterial pressure

Capillary Hydrostatic Pressure (CHP)

The pressure exerted by blood against the wall of a capillary

Venous Pressure

The pressure exerted on the walls of the veins by the circulating blood

Interstitial Fluid Hydrostatic Pressure (IFHP)

The opposing pressure to CHP; rises as fluid exits the capillaries into tissues

Net Hydrostatic Pressure

Difference between the pressure inside the capillaries and the pressure outside the capillaries (CHP - IFHP)

Blood Colloid Osmotic Pressure (BCOP)

Pressure created by the concentration of colloid proteins in the blood

Interstitial Fluid Colloid Osmotic Pressure (IFCOP)

Pressure exerted by the colloids within the interstitial fluid

Net Colloid Osmotic Pressure

Difference between the pressure exerted by capillary plasma proteins and tissue plasma proteins (BCOP - IFCOP)

Peripheral Resistance

Resistance of the arteries to blood flow

Pulse

Rhythmic pressure oscillation following each heartbeat

Pulse Pressure

Difference between systolic & diastolic pressures

Sphygmomanometer

A pressure gauge for measuring blood pressure

Autoregulation

Vasodilators control diameter by relaxing the smooth muscle; vasoconstrictors stimulate the vessel sphincters

Neural Mechanisms

Cardiovascular centers have acceleration and inhibition actions. Adrenergic - vasoconstriction; Cholinergic - vasodilation

Baroreceptor Reflexes

Carotid & aortic sinus that monitor the stretch of vessel walls

Chemoreceptor Reflexes

Neurons called carotid bodies and aortic bodies; due to CO2, O2, or pH levels

Antidiuretic Hormone

Hormone that regulates water in blood

Erythropoietin

Hormone that controls viscosity of blood

Atrial Natriuretic Peptide

A hormone that decreases blood volume

Epinephrine & Norepinephrine

Hormones that increase blood pressure

Angiotensin II

Hormone that constricts vessels and stimulates aldosterone

Arteriosclerosis

Thickening and toughening of the arteries. Linked to coronary artery disease

Focal Calcification

Type of anteriosclerosis; smooth muscle degenerates & salt deposits are left

Atherosclerosis

Type of anteriosclerosis; smooth muscle degenerates & lipids are left

Aneurysms

Weakened blood vessels bulge, and may eventually burst. In brain = stroke; in heart = sudden death

Cerebrovascular Accident (CVA)

Loss of blood flow to part of the brain, damages brain tissue; stroke

Transient Ischemic Attack (TIA)

Small stroke; usually proceeds CVA's

Varicose Vein

A vein that is permanently dilated; most common in the legs

Phlebitis

Inflammation of a vein

Hypotension

Abnormally low blood pressure; less than 90/60 mmHg

Hypertension

High blood pressure; anything over 130/80 mmHg

Cardiogenic Shock

Failure of the heart to pump effectively

Obstructive Shock

Due to physical obstruction of the great vessels (or heart)

Hypovolemic Shock

Happens when there isn’t enough blood in your blood vessels to carry oxygen to your organs

Distributive Shock

Shock caused by poor distribution of the blood flow

Raynaud's Disease

Causes areas of your body, fingers and toes, to feel numb & cold in response to cold temperatures or stress

Patent Foramen Ovale & Patent Ductus Arteriosis (PDA)

Two types of congenital vessel defect where the foramen ovale remains open; aorta shunts blood to pulmonary trunk

Atrioventricular Septal Defect

A type of congenital vessel defect where the walls between the right and left ventricles and/or atria and ventricles are open

Tetralogy of Fallot

A congenital vessel defect composed of 4 defects: Pulmonary stenosis, incomplete interventricular septum, overriding aorta, and enlarged right ventricle

Transposition of the Great Vessels

Aorta and pulmonary trunk are switched - blood routed to wrong ventricles