BSCI202 Lab Practical #2

Which body regions do the superior/inferior vena cava drain?

-superior vena cava: drains head and arms
-inferior vena cava: drains lower body

veins draining into superior vena cava

-arm: radial/ulnar, (basilic → ) brachial, cephalic → axillary → subclavian vein
-head/neck: external jugular vein → subclavian vein + vertebral vein + internal jugular vein

1. subclavian/vertebral/internal jugular → L/R brachiocephalic veins

2. brachiocephalic veins join to form superior vena cava

3. azygous vein drains thorax

veins draining into inferior vena cava

-legs: posterior tibial → popliteal → femoral → external iliac vein, great saphenous veins receive superficial drainage

-gonads: right gonadal vein drains right ovary/testicle, left gonadal vein → left renal vein → kidneys
-digestive organs: hepatic portal vein → liver → L/R hepatic veins → systemic circulation

Pulmonary circulation

1. pulmonary arteries carry deoxygenated blood to lungs

2. capillary beds around alveoli permit gas exchange (CO2 for O2)

3. pulmonary veins empty oxygenated blood into left atrium
   
   -nourishing blood supply for lungs is provided by bronchial arteries

cerebral arterial circulation (circle of Willis): function + pathway

-function: ensures if one major artery to brain is blocked, blood can still reach vital tissues
-pathway:

1. blood reaches circle through L/R internal carotid arteries and L/R vertebral arteries

2. interior carotid divide into anterior and middle cerebral that supply cerebrum

3. vertebral arteries form basilar artery to supply brain stem and cerebellum

4. basilar artery divides into posterior cerebral arteries to supply posterior cerebrum

5. communicating arterial branches unite anterior and posterior blood supplies

hepatic portal circulation: function + pathway

-function: blood coming from digestive organs(stomach/intestines)/spleen/pancreas is nutrient-rich and potentially toxic, so the liver cleans blood and stores nutrients before blood reaches rest of body
-pathway: double capillary bed
1. capillary beds of digestive system absorb nutrients/toxins

2. hepatic portal vein (superior mesenteric + splenic + inferior mesenteric) carries blood to liver

3. hepatocytes (liver cells) help maintain proper nutrient concentration and filters toxins

4. blood drains into hepatic vein as it leaves liver

5. blood returns to inferior vena cava

fetal circulation

-fetus exchanges gases/nutrients/wastes through placenta
-umbilical cord contains three vessels: umbilical vein (carries rich blood to) and two umbilical arteries (carry waste from fetus to placenta)

-blood flow bypasses liver through ductus venosus → inferior vena cava
-blood flow bypasses lungs through foramen ovale (ductus arteriosus connects aorta and pulmonary trunk)

coronary circulation: function + pathway

-function: blood in the heart chambers doesn’t nourish the myocardium so this is how
1. coronary arteries branch from aorta to supply heart muscle with oxygenated blood

2. cardiac veins drain the myocardium of blood

3. the coronary sinus (large vein on heart posterior) receives blood from cardiac veins

4. blood empties into right atrium via sinus

-interarterial anastomoses are back-up plans

what structures of the fetal circulation system are absent in newborns

-forman ovale → fossa ovalis
-ductus arteriosus → ligamentum arteriosum
-ductus venosus → ligamentum venosum
-umbilical vein → ligamentum teres
-umbilical arteries → medial umbilical ligaments

what organs are associated with the hepatic portal circulation system

small/large intestine, stomach, spleen, pancreas, galbladder, liver

Microscopic structure of veins

-much thinner tunica intima than arteries with VALVES to prevent backflow
-very thin tunica media to make veins highly stretchy so can hold large volumes of blood
-thickest layer is tunica externa

Microscopic structure of arteries

-tunica intima: distinct stretchy membrane to allow for expansion
-thickest layer is tunica media

Microscopic structure of capillaries

-don’t have tunica media or tunica externa
-made of single layer of endothelial cells (tunica intima)
-can be continuous, fenestrated (“windows”), or sinusoids (large holes)

arteries: characteristics, special features and adaptations

-function: transport blood away from heart
-expands during systole
-recoils passively during diastole
-elastic arteries: close to the heart, large, “conducting vessels”, most expandable
-muscular arteries: medium-sized, “distributing vessels”, named arteries in the body
-arterioles: smallest, “resistance vessels”

veins: characteristics, special features and adaptations

-holds large amount of blood volume
-low pressure vessels because of thin walls and large lumens
-valves: formed by folds of tunica intima to prevent backflow, especially in the limbs
-skeletal muscle pump
-respiratory pump

capillaries: characteristics, special features and adaptations

-narrowest vessels
-one cell layer walls (endothelium)

What are the three tunics of blood vessels from inner to outer? What tissues make up each tunic? What is the function of each tunic?

-tunica intima: thin layer of simple squamous endothelium with CT basement membrane, create a slick, low-friction surface for blood flow while being a selective barrier for chemicals
-tunica media: smooth muscle and elastic CT, vasoconstriction/vasodilation (changes in lumen diameter) to regulate blood flow
-tunica externa: areolar or fibrous CT, protects and anchors vessels

What is the largest artery in the body? What are the major blood vessels branching off of this artery?

aorta
-ascending aorta: R/L coronary arteries serve the heart
-aortic arch: brachiocephalic trunk, left common carotid artery, left subclavian artery
-descending aorta: intercostal arteries, bronchial arteries, esophageal arteries, phrenic arteries
-abdominal aorta: celiac trunk, superior mesenteric artery, renal arteries, gonadal arteries, lumbar arteries, inferior mesenteric arty, common iliac arteries

brachiocephalic trunk splits into

right common carotid artery and right subclavian artery

left common carotid artery splits into

left internal and external carotid arteries

left subclavian artery splits into

branches into left vertebral and left subclavian artery, then the subclavian artery becomes axillary → brachial → radial and ulnar arteries

three branches of the celiac trunk

left gastric artery (stomach), splenic artery (spleen), common hepatic artery (liver)

function of superior mesenteric vs inferior mesenteric arteries

superior: supplies most of small intestine and first half of large intestine

inferior: supplies second half of large intestine

function of lumbar arteries

serves muscles of abdomen and trunk

function of the L/R common iliac arteries

-internal: serve pelvic organs
-external: enter thigh to become femoral → popliteal → anterior and posterior tibial arteries

Define systole and diastole.

-systole: the heart muscle contracts, pushing blood out of the chambers and into arteries
-diastole: heart muscle relaxes and chambers fill with blood

What is the order of events in the cardiac cycle? Be able to relate this to diastole and systole.

1. passive ventricular filling (mid-to-late diastole): event flows passively from veins into atria and through open atrioventricular valves into ventricles

2. atrial contraction (atrial systole): SA node fires, causing atria to contract while ventricles remain in diastole. This kicks the remaining blood into the ventricles so that the ventricles contain max volume for the cycle (end diastolic volume)

3. isovolumetric contraction (start of ventricular systole): atria relax (diastole), ventricles begin systole, AV valves slam shut to prevent backflow as ventricular pressure rises

4. ventricular ejection (ventricular systole continued): ventricular pressure finally exceeds pressure in large arteries so the semilunar valves open and blood is explosively ejected into circulation (stroke volume)

5. isovolumetric relaxation (early diastole): ventricles enter diastole, pressure drops, semilunar valves shut because aorta blood tries to flow back into heart

What event produced the “lub” sound during the cardiac cycle? The “dub” sound?

-”lub”: AV valves shut to prevent backflow into atria
-”dub”: semilunar valves shut to prevent backflow into heart

What tool would you use to listen to heart sounds?

stethoscope

how to calculate heart rate from heart beat length

HR = 60 seconds/heart beat duration

At what points on the body (at what arteries) can pulse be measured?

radial and carotid pulses

What tool would you use to measure blood pressure?

sphygmomanometer, measured in mmHg and expressed as SBP/DBP

SBP vs DBP

-systolic blood pressure: pressure exerted against walls of arteries during ventricular systole
-diastolic blood pressure: pressure exerted against the arterial wall during ventricular diastole

how to tell if someone is in a blood pressure category

-normal: <120/<80
-elevated: 120-129/<80
-high blood pressure stage 1: 130-139SBP OR 80-89DBP
-high blood pressure stage 2: 140+ SBP OR 90+ DBP
-hypertensive crisis: 180+ SBP OR 120+ DBP

What are the basic steps for measuring blood pressure in a subject at rest?

1. place blood pressure cuff on upper left arm

2. place stethoscope on brachial artery

3. inflate pressure in cuff until circulation is cut off (<160mnHg)

4. use valve to slowly release pressure

5. pressure reading at first sound heard = SBP (sounds of Korotkoff)

6. pressure reading when sound disappears = DBP

What is the equation that can be used to measure arterial blood pressure? What are the roles of cardiac output and peripheral resistance on blood pressure?

BP = CO (cardiac output) x TPR (total peripheral resistance)

-cardiac output: the amount of blood pumped by heart in one minute (CO=SVxHR) - increased heart rate → increased CO → more blood in arteries → increased pressure
-peripheral resistance: amount of force exerted on circulating blood by the vasculature - smaller vessel diameter → high BP, thicker blood is hard to push, longer vessel length → increased friction

What are the structures of the upper respiratory system?

Some of the structures of the upper respiratory system have both respiratory and digestive functions. What are these structures? What are the structures that have only respiratory functions?

There are a number of different cartilaginous structures in the respiratory system. What are they? What are the different types of cartilage in each of these structures?

What are the structures of the lower respiratory system?

How are the left and right main bronchi different?

How are the left and right lungs different?

What tool would you use to measure respiration volumes?

What are the average respiratory volumes for males and females? What about the average respiratory capacities?

How would you use a spirometer to measure tidal volume? Inspiratory reserve volume (only possible with iWorx spirometer in this class)? Expiratory reserve volume?

What factors influence the rate and depth of respiration?

How does breathing impact pulse?

What buffer system operates in blood plasma and red blood cells? Which component of the buffer system resists a drop in pH? What resists a rise in pH?

Briefly explain how the carbonic acid-bicarbonate buffers system of the blood operates?

What is the role of the chloride shift?

What is hypoventilation? Hyperventilation?

What happens to the amount of carbonic acid in the blood during hypoventilation? During

hyperventilation?

What is respiratory acidocis? Respiratory alkalosis?

What types of tissue is the larynx made of?