lec test 3

Which layer of the heart makes contact with blood?

Endocardium

What do atrioventricular (AV) valves prevent?

Backflow of blood from ventricles into atria

What is the left AV valve called?

Mitral (bicuspid) valve

What is the right AV valve called?

Tricuspid valve

What do semilunar valves prevent?

Backflow of blood into the ventricles

What are the support structures of heart valves?

Chordae tendineae and Papillary muscles

What is cardiac circulation?

Blood flowing through the heart chambers

What is pulmonary circulation?

Deoxygenated blood getting reoxygenated in the lungs

What is systemic circulation?

Oxygenated blood going to the entire body

What blood vessels supply oxygenated blood to the heart muscle (myocardium)?

Coronary arteries (from ascending aorta)

What blood vessels supply oxygenated blood to lung tissue?

Right and left bronchial arteries

What blood vessels drain deoxygenated blood from lung tissue?

Bronchial veins

Where does deoxygenated blood from the heart muscle drain?

Coronary sinus → Right atrium

What veins bring deoxygenated blood from the upper body to the right atrium?

Superior vena cava

What veins bring deoxygenated blood from the lower body to the right atrium?

Inferior vena cava

What does the SA node do?

Sends an electrical impulse that shocks the heart to contract

How is the conduction system measured?

Electrocardiogram (ECG/EKG)

What does the P wave in an ECG represent?

Atrial depolarization (atria contract; blood goes to ventricles)

What does the QRS complex in an ECG represent?

Ventricular depolarization (ventricles contract; blood leaves the heart)

What does the T wave in an ECG represent?

Ventricular repolarization (ventricles relax)

What heart sound is associated with AV valves closing?

S1 (lubb) – AV valves shut

What heart sound is associated with semilunar valves closing?

S2 (dupp) – semilunar valves shut

What is cardiac output (CO)?

The volume of blood ejected from the left ventricle each minute

What is the formula for cardiac output?

CO = Stroke Volume × Heart Rate

What is a normal stroke volume?

70 mL/beat

What are the three layers (tunics) of blood vessel walls from inner to outer?

Tunica intima (interna) , Tunica media, Tunica externa (adventitia)

What is the tunica intima made of?

Simple squamous epithelium (endothelium) – makes contact with blood

What is the tunica media made of?

Muscular layer (smooth muscle + elastic fibers)

What is the tunica externa (adventitia) made of?

Connective tissue (collagen + elastic fibers)

What is the lumen?

The hollow center of a blood vessel through which blood flows

What is vasodilation?

Increase in the diameter of the lumen (widens vessel)

What is vasoconstriction?

Decrease in the diameter of the lumen (narrows vessel)

What do veins have that arteries do not?

Valves (prevent backflow of blood)

What are large arteries that come off the heart and aorta called?

Elastic arteries (conducting arteries)

What is the function of elastic arteries?

Stretch to withstand the surge of blood from the heart

What is the function of muscular arteries?

Can dilate or constrict to distribute blood to specific areas

What is an anastomosis?

Collateral circulation – major organs have a double blood supply (2 or more arteries supplying the same body region)

What is edema?

Increase in interstitial fluid when the balance of filtration and reabsorption is disrupted

What is a pulse?

The alternate expansion and recoil of elastic arteries after each systole (heart contraction)

What is tachycardia?

Resting heart rate greater than 100 bpm

What is bradycardia?

Resting heart rate less than 50 bpm

What is auscultation?

Listening to body sounds with a stethoscope

What artery is used to measure blood pressure?

Brachial artery

What instrument is used to measure blood pressure?

Sphygmomanometer (blood pressure cuff)

What are the Korotkoff sounds?

The sounds heard when taking blood pressure

What are the three functions of the lymphatic system?

1. Drain interstitial fluid; 2. Transport dietary lipids and fat-soluble vitamins (A, D, E, K); 3. Fight infection via immune responses

How do lymph capillaries begin?

As blind-ended vessels that intertwine with blood capillaries

What is the flow of lymph?

1. From arteries and blood capillaries (blood)

2. To interstitial spaces (interstitial fluid)

3. To lymph capillaries (lymph)

4. To lymphatic vessels

5. To lymphatic trunks

6. To Thoracic duct or Right Lymphatic Duct

7. To Subclavian veins (blood returns to bloodstream)

What is the main collecting duct of the lymphatic system?

Thoracic duct

What does the thoracic duct drain?

The lower half of the body and the upper left half of the body

What trunks drain into the thoracic duct?

Left lumbar, intestinal, left bronchomediastinal, left subclavian, left jugular

What does the right lymphatic duct drain?

The upper right side of the body

What trunks drain into the right lymphatic duct?

Right jugular, right subclavian, right bronchomediastinal

What veins do the lymphatic ducts empty into?

Right and left subclavian veins → Superior vena cava

What are the primary lymphatic organs?

Red bone marrow and Thymus gland

What does red bone marrow produce?

Pre-T lymphocytes and B cells

Where do T cells mature?

Thymus gland (sits on top of the pericardium)

What are the secondary lymphatic organs?

Lymph nodules, lymph nodes, and spleen

What are lymph nodules?

Oval-shaped concentrations of tissue in mucous membranes (MALT)

ex. tonsils

What is the largest lymphatic organ? Where is it located?

Spleen, left hypochondriac region

What does the white pulp of the spleen do?

Where B cells proliferate → produce antibodies (fight infection)

What does the red pulp of the spleen do?

Phagocytosis – removes bacteria, worn-out RBCs, and platelets

What is resistance?

The ability to ward off disease

What is susceptibility?

The lack of resistance

What is the first line of defense? Give examples.

Mechanical and chemical barriers

Mechanical: Intact skin, tears (lacrimal apparatus), urination, defecation, vomiting

Chemical: Sebum (low pH), lysozyme (sweat), gastric juice (low pH)

What is the difference between mechanical and chemical barriers?

Mechanical = physical removal/blocking; Chemical = substances that kill or inhibit microbes

What is the second line of defense?

Internal defenses – interferons, phagocytes, natural killer cells, inflammation, fever

What are interferons?

Proteins produced by virus-infected cells that protect neighboring cells from viruses

What are the four stages of phagocytosis?

Stage	Description
1. Chemotaxis	Chemical attraction of phagocytes to a particular location
2. Adherence	Phagocyte attaches to the microbe
3. Ingestion	Pseudopods engulf the microorganism
4. Killing	Microbe is destroyed

What is immunology?

The study of the immune system

What is cell-mediated immunity?

Cells attacking cells – T cells attack virus-infected cells, tumor cells, and transplanted tissue cells

What is humoral (antibody-mediated) immunity?

Antibodies attacking foreign antigens (bacteria, toxins in body fluids)

What are antibodies?

Proteins that bind to specific antigens and mark them for destruction

What is IgG?

The most abundant antibody; can pass through the placenta (mother to fetus)

What is IgA?

Antibody found in mother's milk (breastfeeding); provides passive immunity to baby. Provides localized protection on mucous membranes.

Naturally acquired active immunity

Exposure to antigen → body makes its own antibodies

Naturally acquired passive immunity

Mother to fetus (through placenta) or breastfeeding

Artificially acquired active immunity

Vaccination

Artificially acquired passive immunity

IV injection of immunoglobulins (pre-made antibodies)