A&PII General Review

What is the formula for Cardiac Output (CO)?

= Stroke Volume (SV) x Heart Rate (HR)

What is the normal average Cardiac Output?

5 liters per minute;

it takes approximately 1 minute for blood to complete a full circuit through the body's ~5 liters of blood

What is the formula for Pulse Pressure?

= Systolic Pressure - Diastolic Pressure

What is the normal pulse pressure?

40 mmHg (120 - 80 = 40 mmHg)

What does a narrow pulse pressure (e.g., 20 mmHg) indicate?

Narrowing or hardening of the arteries (arteriosclerosis/hardening of blood vessels)

What does the Celiac Trunk supply? (mnemonic)

Liver, Spleen, Stomach (LFS)

During fight-or-flight, blood flow DECREASES to which organs?

Reproductive system, intestines/digestive system, and kidneys

During fight-or-flight, blood flow INCREASES to which organs?

Coronary arteries (heart), skeletal muscles, and lungs

What do lymph nodes contain that produce antibodies?

Plasma cells, which produce antibodies (immunoglobulins)

What is venous return?

The blood coming back to the heart.

Name the 4 factors that increase venous return.

1) Increased depth of breathing

2) Exercise/vigorous walking

3) Increased heart rate/ventricular contraction

4) Activation of the sympathetic nervous system (venoconstriction)

What is the function of the esophagus?

Transports food from the pharynx to the stomach; does NOT perform any chemical digestion

What are the 4 layers of the GI tract wall (inside to outside)?

1. Mucosa

2. Submucosa

3. Muscularis externa

4. Serosa (or adventitia)

Only 2 locations in the body have microvilli (brush border). Name them.

• Small intestine (mucosa)

• Proximal Convoluted Tubule (PCT) of the kidney

What are the key functions of the liver?

• Metabolism of carbohydrates, fats, and proteins

• detoxification

• synthesis of plasma proteins

• production/secretion of bile

• storage of glycogen, fat-soluble vitamins, and iron

What produces Intrinsic Factor and what is its purpose?

Parietal cells of the stomach

required for absorption of Vitamin B12 in the terminal ileum

What is Pernicious Anemia?

A type of megaloblastic anemia caused by Vitamin B12 deficiency due to lack of Intrinsic Factor

What is the most common cause of generalized edema?

Decreased protein in the blood (hypoproteinemia/hypoalbuminemia); low plasma oncotic pressure causes fluid to leak into tissues

Why do iron requirements increase during pregnancy?

The mother needs iron to make RBCs for herself AND the developing baby

RBCs must also be maintained within the placenta

overall metabolism increases

Name all components of the nephron in order.

1. Glomerulus

2. Bowman's Capsule

3. Proximal Convoluted Tubule (PCT)

4. Loop of Henle

5. Distal Convoluted Tubule (DCT)

6. Collecting Duct

What is the function of the glomerulus?

Cluster of capillaries where blood is filtered into Bowman's capsule

What is the function of the PCT (Proximal Convoluted Tubule)?

Major site of reabsorption

lined with microvilli (brush border)

What is the function of the Loop of Henle?

Creates the osmotic gradient in the medulla (descending and ascending limbs)

What is the function of the DCT (Distal Convoluted Tubule)?

Fine-tuning of filtrate

responds to hormones (aldosterone, ADH)

What is the function of the Collecting Duct?

Final urine concentration

major site of ADH action

What is an important property of transitional epithelium in the nephron?

It is IMPERMEABLE - prevents urine from leaking into surrounding tissues

What is Excretion?

The process of eliminating metabolic waste products from the body (urea, uric acid, creatinine, and other waste metabolites)

What is the Effective Filtration Pressure (EFP) formula?

= Outward forces (hydrostatic) - Inward forces (osmotic)

If EFP is POSITIVE, what occurs?

net filtration (fluid moves from A to B)

If EFP is NEGATIVE, what occurs?

net reabsorption (fluid moves from B to A)

What is the Rate of Filtration formula?

= EFP x Filtration Coefficient (Kf)

What is the Filtration Fraction?

The filtered fluid that enters Bowman's capsule; equals Plasma minus Proteins (proteins do not pass through the glomerular membrane); GFR/Renal Plasma Flow

What is the most important principle in kidney physiology regarding sodium and water?

Water follows sodium - wherever sodium goes, water follows by osmosis

if sodium reabsorption is blocked, water stays in the tubule and is excreted (diuresis)

How does Lasix (furosemide) work?

Blocks sodium (Na+) reabsorption in the Loop of Henle; sodium stays in tubule → water follows → both excreted in urine; used to treat edema, pulmonary edema, and hypertension

What is the function of ADH (Antidiuretic Hormone)?

Promotes water reabsorption in the collecting duct, concentrating the urine

without it → dilute, large-volume urine (diabetes insipidus)

What is SIADH?

Syndrome of Inappropriate ADH secretion

too much ADH → too much water retained → increased blood volume → increased blood pressure (hypertension)

What are the components of the cardiovascular system?

Heart (cardio) and blood vessels (vascular)

What is the main function of the heart?

To pump blood throughout the body

it is the prime mover of circulation

What are the two synergistic factors that help the heart with circulation?

1) Elastic tissue in blood vessels (recoils after expansion)

2) Skeletal muscle contraction (squeezes blood vessels)

What is the difference between arteries and veins?

Arteries carry oxygenated blood AWAY from the heart (appear red)

veins carry deoxygenated blood TOWARD the heart (appear blue)

What is the blood vessel size hierarchy from heart outward?

Artery → Arteriole → Capillary → Venule → Vein

What are the three components of the Peripheral Vascular Bed?

• Arterioles

• Capillaries

• Venules

Where does gas exchange occur in the cardiovascular system?

At the capillary level

capillaries are microscopic and made of simple epithelium

What is the mediastinum?

The space between the two lungs

contains the heart, great vessels, part of trachea, and part of esophagus

What is the normal size and weight of the heart?

Size of your own fist (when filled with blood)

weighs 250-350 grams

How much oxygen deprivation causes damage to the heart muscle?

4-6 minutes without oxygen causes damage to heart muscle

What is CPR's effectiveness?

Provides 30% of normal heart function; 30% is enough to supply the brain and maintain viability

What is the shape and orientation of the heart?

Inverted cone shape (upside-down triangle)

pointed end at bottom = apex

broad end at top = base; 2/3 to the LEFT of midline

What is the Point of Maximum Impulse (PMI) and where is it located?

The pointed, prominent part at the bottom (apex) where contraction starts

located at the 5th intercostal space, midclavicular line, 7.5 cm from midline on the left

What is Dextrocardia?

A congenital condition where the heart points to the RIGHT instead of LEFT; occurs in 1-2% of population; may have situs inversus (reversal of all organs)

What are the two main layers covering the heart?

1) Fibrous Pericardium (outer - tough, anchors heart), 2) Serous Pericardium (inner - transparent, very vascular)

What are the two sublayers of the serous pericardium?

Parietal layer (outer, lines fibrous pericardium)

Visceral layer (inner, also called epicardium; stuck to heart muscle)

What is the pericardial cavity?

Space between parietal and visceral layers of serous pericardium

contains serous fluid (10-15cc) for lubrication and frictionless movement

What is Cardiac Tamponade?

• Too much fluid in the pericardial cavity

• restricts heart expansion

• can be FATAL

• most common cause is bleeding into pericardial space (often after open heart surgery)

• treatment = pericardiocentesis

What are the 3 layers of the heart wall?

1) Epicardium (outer - same as visceral serous pericardium)

2) Myocardium (middle - thickest, cardiac muscle, runs in WHORLS)

3) Endocardium (inner - smooth connective tissue lining)

What are the 4 chambers of the heart and their functions?

• Right atrium (receive blood from body)

• Left atrium (receive blood from lungs)

• Right ventricle (pump to lungs)

• Left ventricle (pump to body)

Which ventricle is thicker and why?

Left ventricle is thicker because it pumps blood into the aorta and to every cell in the body

right ventricle only pumps to the lungs

What are the AV valves and where are they located?

Tricuspid valve (3 cusps) on the right between right atrium and ventricle

Bicuspid/Mitral valve (2 cusps) on the left between left atrium and ventricle

What are chordae tendineae and papillary muscles?

Papillary muscles are pyramid-shaped muscles in ventricles that anchor valve leaflets; chordae tendineae are cord-like structures connecting papillary muscles to valve leaflets, keeping them from prolapsing

What is Mitral Valve Prolapse?

Occurs when chordae tendineae are too long or papillary muscles are damaged

valve doesn't close tightly → blood leaks back into atrium

most common valve prolapse

What are the semilunar valves?

guard exits from ventricles

• Pulmonary semilunar valve (between right ventricle and pulmonary trunk)

• Aortic semilunar valve (between left ventricle and aorta)

shaped like half-moons

Describe blood flow through the right side of the heart.

Right atrium → Tricuspid valve → Right ventricle → Pulmonary semilunar valve → Pulmonary trunk/artery → Lungs

Describe blood flow through the left side of the heart.

Lungs → Pulmonary veins → Left atrium → Bicuspid/Mitral valve → Left ventricle → Aortic semilunar valve → Aorta → Body

What are the 4 sources of blood for the right atrium?

Superior vena cava, Inferior vena cava, Coronary sinus, Minute coronary veins (Thebesian veins)

What are the 4 sources of blood for the left atrium?

• Right superior pulmonary vein

• Right inferior pulmonary vein

• Left superior pulmonary vein

• Left inferior pulmonary vein

What are unique features of cardiac muscle?

• More mitochondria than skeletal muscle

• less calcium (prevents tetanus)

• intercalated discs (gap junctions for electrical spread and synchronized contraction)

What is the cardiac conduction system in order?

SA node → Internodal fibers → AV node (delay) → Bundle of His → Left and Right Bundle Branches → Purkinje fibers → Ventricular muscle

What is the SA node?

Sinoatrial node; the PACEMAKER of the heart; located in the posterior wall of right atrium below superior vena cava; fires at 70-80 beats/minute

What is the AV node?

Atrioventricular node

located on the floor of right atrium near interatrial septum

creates a TRANSMISSION DELAY to allow atria to contract before ventricles

backup pacemaker rate 40-60 bpm

What happens if the SA node fails?

AV node becomes pacemaker at 40-60 bpm

patient feels dizzy, may pass out

requires artificial pacemaker

What happens if BOTH SA and AV nodes fail?

Purkinje fibers become pacemaker at 15-40 bpm

emergency situation

What are the 3 layers of blood vessel walls?

1) Tunica Intima (inner - endothelium, smooth surface)

2) Tunica Media (middle - smooth muscle, elastic tissue)

3) Tunica Adventitia/Externa (outer - connective tissue)

What structural differences distinguish arteries from veins?

Arteries: thicker walls, more smooth muscle, elastic fibers, smaller lumen, no valves, pulsate;

Veins: thinner walls, less smooth muscle, larger lumen, have VALVES, usually don't pulsate

What percentage of blood is in veins at any given moment?

60%

(high capacitance due to thin walls and large lumen)

What is an Aneurysm?

Dilation (widening) of an artery

creates a thin wall

risk of rupture especially with high blood pressure

aortic aneurysm rupture = lose 1 liter/minute (only ~4 minutes with 5L total blood)

What is Atherosclerosis?

Buildup of cholesterol (soft fatty plaque) in artery walls

narrows lumen, thickens wall, creates rough surface → platelet activation → blood clot formation → complete blockage

major cause of heart attacks and strokes

What are the regions of the Aorta?

Ascending aorta → Arch of aorta → Descending aorta (thoracic above diaphragm, abdominal below diaphragm) → Bifurcates at umbilicus into Common Iliac arteries

What are the 3 branches of the Arch of Aorta?

1) Brachiocephalic Trunk (innominate artery) - divides into right common carotid and right subclavian, 2) Left Common Carotid Artery, 3) Left Subclavian Artery

What is the Circle of Willis?

Circular arterial connection at the base of the brain formed by 2 vertebral arteries + 2 internal carotid arteries

provides collateral circulation if one vessel is blocked

discovered by Willis

What are the major branches of the Abdominal Aorta?

Celiac trunk (liver, stomach, spleen), Renal arteries (kidneys), Superior mesenteric artery (small intestine, part of large intestine), Inferior mesenteric artery (intestines); terminates as Common Iliac arteries

List the major pulse palpation points from head to foot.

Temporal → Facial → Carotid (ONE SIDE ONLY) → Brachial → Radial → Femoral → Popliteal → Posterior tibial → Dorsalis pedis

What is the Great/Long Saphenous Vein?

The longest vein in the body

runs from groin to ankle;

superficial; used for bypass surgery (must REVERSE when connecting to coronary arteries)

What is the Hepatic Portal System?

Blood from intestines → capillaries → hepatic portal vein → liver (second capillary network) → allows liver to process nutrients before blood returns to heart

How long is one cardiac cycle?

0.8 seconds (800 milliseconds)

What is Systole?

contraction phase of the heart

What is Diastole?

relaxation phase of the heart

How long is ventricular systole?

~0.3 seconds

How long is ventricular diastole?

~0.5 seconds

the heart rests MORE than it works

What is End Diastolic Volume (EDV)?

Maximum volume of the ventricle = 130 mL

occurs at the END of diastole when ventricle is completely filled

What is End Systolic Volume (ESV)?

Minimum volume of the ventricle = 60 mL

blood remaining in ventricle AFTER contraction

What is Stroke Volume (SV)?

Amount of blood ejected from ventricle with each beat

SV = EDV - ESV = 130 - 60 = 70 mL per beat

What is the Ejection Fraction (EF) and how is it calculated?

= (SV / EDV) x 100

Normal = ~60%

Heart failure = 30% or lower

indicates how efficiently heart is pumping

What is Cardiac Output?

= SV x Heart Rate

Normal = 70 mL/beat x 70 beats/min = ~4,900 mL/min ≈ 5 liters/min

heart pumps entire blood volume every minute

What are the two phases of ventricular systole?

1) Isovolumetric Contraction (ventricle contracts, all valves closed, volume stays at 130 mL, building pressure to open aortic valve)

2) Ventricular Ejection (aortic valve opens, volume drops from 130 to 60 mL)

What is Isovolumetric Contraction?

• Phase when ventricle is contracting but no blood is ejected

• all valves are closed

• volume stays constant at 130 mL

• building enough pressure to overcome aortic pressure and open aortic valve

What do the heart sounds S1 represent?

(Lub) = closure of AV valves (bicuspid + tricuspid)

marks beginning of ventricular systole

What do the heart sounds S2 represent?

(Dup) = closure of semilunar valves (aortic + pulmonary)

marks beginning of ventricular diastole

What is the significance of S3 and S4 heart sounds?

Normal in children; ABNORMAL in adults - indicates heart problems

What does the P wave represent on an EKG?

Atrial depolarization

occurs just BEFORE atrial contraction (atrial systole)

What does the QRS complex represent on an EKG?

Ventricular depolarization; occurs just BEFORE ventricular contraction; also includes hidden atrial repolarization