BIO 202 Exam 2

Where is the heart located?

Located in the thoracic cavity, between the lungs, and lies within the inferior mediastinum

What are the three layers of the heart?

Epicardium, Myocardium, and Endocardium

What is the thickest layer of the heart?

The myocardium

Description of the Epicardium:

The outer, visceral pericardium

Description of the Myocardium:

Cardiac muscle, thickest

Description of the endocardium:

Inner lining, continuous with vessels

describe the atrial chambers

thin walled and receive blood

describe ventricle chambers

thick-walled and pump blood

what is special about the left ventricle?

It is the strongest systemic trunk

What are the AV valves?

Tricupsid (R), and Bicupsid/mitral (L)

What are the semilunar valves?

Semilunar valves permit blood to flow forward into the major arteries while preventing it from flowing backward. This includes the pulmonary and aoritc valve.

What does the chordae tendinae do?

they anchor the AV valves and prevent them from inverting or prolapsing backward when the heart contracts

Why is the myocardium thicker in the ventricles than in the atria?

Ventricles must generate more force to pump blood out of the heart.

What are the four chambers of the heart?

Right atrium, Right ventricle, Left atrium, Left ventricle

Which side of the heart pumps blood to the lungs?

The right side

Which side of the heart pumps blood to the body?

The left side

What is the cardiac skeleton?

A dense connective tissue framework within the heart.

What are the functions of the cardiac skeleton?

Supports heart valves

Provides attachment for cardiac muscle

Electrically insulates atria from ventricles

Forces impulses through the AV node

Which arteries carry deoxygenated blood?

Pulmonary arteries

Which veins carry oxygenated blood?

Pulmonary veins.

What is coronary circulation?

Blood supply to the heart muscle (myocardium)

Which arteries branch from the left coronary artery (LCA)?

Left anterior descending (LAD)

Circumflex artery

Which arteries branch from the right coronary artery (RCA)?

Marginal artery and posterior interventricular artery

Where do cardiac veins drain into?

Coronary sinus

Into which chamber does the coronary sinus empty?

Right atrium

What is systole?

The contraction phase of the heart.

What is diastole?

The relaxation and filling phase of the heart.

What causes the first heart sound (S1, "lubb")?

Closure of the AV valves

What causes the second heart sound (S2, "dubb")?

Closure of the semilunar valves.

Which phase is associated with ventricular filling?

Diastole

What is the normal conduction pathway of the heart?

SA node → AV node → Bundle of His → Right & Left Bundle Branches → Purkinje fibers

What is the pacemaker of the heart?

SA node

What does the AV node do and why?

The AV node delays the impulse from SA node to allow the atria to finish contracting before the ventricles contract.

What do Purkinje fibers do?

Rapidly distribute impulses through ventricular myocardium, causing ventricular contraction.

What does the P wave represent?

Atrial depolarization

What does the QRS complex represent?

Ventricular depolarization.

What does the T wave represent?

Ventricular repolarization.

When does the atria repolprize?

During the QRS complex

What is the formula for cardiac output?

CO = HR × SV

What does cardiac output represent?

The volume of blood pumped by one ventricle per minute.

What does HR stand for?

heart rate

What does SV stand for?

Stroke volume.

What is cardiac output influenced by?

Heart rate, Preload, Contractility, Afterload, Autonomic nervous system activity

What is preload?

The amount of ventricular stretching before contraction

What is contractility?

The force of ventricular contraction

What is afterload?

The resistance the ventricles must overcome to eject blood.

What is valve stenosis?

Narrowing of a heart valve that restricts blood flow.

What is valve regurgitation?

Leakage of blood backward through a valve.

What is myocardial infarction?

Death of heart muscle due to blockage of a coronary artery.

What is left-sided heart failure commonly associated with?

affects the lungs, causing breathing issues and fatigue

What is right-sided heart failure commonly associated with?

Peripheral edema and fluid accumulation.

What direction do arteries carry blood?

Away from the heart.

Why do arteries have thick walls?

To withstand high blood pressure

What effect does vasoconstriction have on blood pressure?

Increases blood pressure.

What effect does vasodilation have on blood pressure?

Decreases blood pressure

What is the primary function of capillaries?

Exchange of gases, nutrients, hormones, and wastes.

Why are capillary walls only one cell thick?

To allow efficient diffusion

What pushes fluid out of capillaries?

Hydrostatic pressure.

What pulls fluid into capillaries?

Osmotic pressure.

What direction do veins carry blood?

Toward the heart.

Why do veins contain valves?

To prevent backflow of blood.

What helps return venous blood to the heart?

Skeletal muscle pump, Respiratory pump, Venous valves

Which vessel layer contains smooth muscle?

Tunica media

Which vessel layer is controlled by the sympathetic nervous system?

Tunica media

Which vessel layer contains smooth endothelium?

Tunica interna

Which vessel layer contains connective tissue?

Tunica externa

Where is blood pressure the highest?

The arteries

Where is blood pressure the lowest?

The veins

What factors increase peripheral resistance?

decreased vessel diameter, increased viscosity, increased vessel length

What receptors monitor blood pressure changes?

Baroreceptors

What is RAAS?

Renin-Angiotensin-Aldosterone System, which raises blood pressure.

How does ADH affect blood pressure?

Increases water retention, raising blood volume and BP.

How does ANP affect blood pressure?

Promotes sodium and water loss, lowering BP.

What is the hepatic portal system?

A specialized network of veins that directs blood from the gastrointestinal tract and spleen directly to the liver

If you were to exercise, what would happen to your blood volume?

Your blood volume would increase due to an expansion of blood plasma.

What resembles a lymphatic vessel and why?

Veins because both have valves

Which veins contribute to the hepatic portal vein?

Gastric veins, Mesenteric veins, Splenic vein

Why does blood pass through the liver before returning to the heart?

Nutrients, toxins, and drugs can be processed before entering systemic circulation.

What are the three major functions of the lymphatic system?

Return excess tissue fluid to blood, Absorb dietary fats, Provide immune defense

What is lymph?

Tissue fluid that enters lymphatic capillaries.

What moves lymph through lymphatic vessels?

Skeletal muscle contractions, Breathing movements, Smooth muscle contractions, One-way valves

What areas drain into the right lymphatic duct?

Right side of the head, right arm, and right thorax.

What areas drain into the thoracic duct?

The rest of the body.

What is the function of lymph nodes?

Filter lymph

What cells are abundant in lymph nodes?

Macrophages and lymphocytes.

What is the flow of lymph through a lymph node?

Afferent vessels → lymph node → efferent vessels.

What is the function of the spleen?

Filters blood, Removes old RBCs, Stores platelets, Immune surveillance

What is the primary function of the thymus?

T-cell maturation

Why is the thymus larger in children?

T-cell development is most active before puberty.

What is innate immunity?

(non-specifc) first and second line of defense. Includes skin, mucous membranes, phagocytic cells, antimicrobial proteins, and inflammatory response.

What is adaptive immunity?

Specific immunity that develops after exposure to pathogens.

Which cells are primarily responsible for adaptive immunity?

B lymphocytes and T lymphocytes.

Where do T and B cells become immunocompetent?

T cells in the thymus and B cells in the bone marrow

What happens to cardiac output (CO) if stroke volume (SV) decreases? What happens to blood pressure?

If stroke volume decreases then the cardiac output would decrease as well because it directly affects it. Blood pressure would also drop because we know that a decrease in stroke volume means lower cardiac output. Therefore blood pressure would decrease because not as much blood is entering the system.

What are the layers and characteristics of blood vessels?

Blood vessels have three layers: the tunica interna, a smooth endothelial lining; the tunica media, composed of smooth muscle and elastic tissue; and the tunica externa, an outer connective tissue layer.

How do veins differ from arteries?

Arteries carry blood away from the heart under high pressure and have thick muscular walls, while veins carry blood toward the heart under low pressure and have thinner walls, larger lumens, and valves.

How do veins differ from lymphatic vessels?

Veins differ from lymphatic vessels because veins carry blood, whereas lymphatic vessels carry lymph and help return excess tissue fluid to the bloodstream while also contributing to immune function.

Pulmonary circuit vs systemic circuit

The pulmonary circuit transports oxygen-poor blood from the right side of the heart to the lungs. The systemic circuit transports oxygen-rich blood from the left side of the heart to body tissues.

What is the frank starling law?

The more the heart muscle is stretched during filling, the stronger it contracts.

What is cardiac reserve?

the difference between a person's maximum cardiac output and their resting cardiac output.