Lab Practical 2

tunica intima

- lines the lumen of a vessel
- composed of endothelium (simple squamous)
- extremely smooth lining that helps decrease resistance to blood flow

tunica media

- middle coat of blood vessel
- composed of smooth muscle and elastin
- regulates the diameter of blood vessels (in turn alters blood flow and pressure)

tunica externa

- outermost tunic of vessel
- composed of areolar or fibrous connective tissue
- supportive and protective function

arteries

- thick walls
- elastic
- acts as a pressure reservoir, expanding and recoiling for continuous blood flow

veins

- large lumens
- low pressure vessels
- return blood to the heart
- valves prevent back flow of blood

arterioles

- smallest arteries
- regulate blood flow to specific areas of the body

venules

- smallest veins
- drain capillary beds and merge to form veins

capillaries

- provide for the exchange of materials between blood and tissue cells
- found between arterioles and venules

what aids in the return of blood to the heart?

- skeletal muscle pump
- pressure changes in the thorax that occur during breathing

aorta

largest artery of the body

pulmonary circulation

- brings blood into close contact with alveoli to permit gas exchanges that rid the blood of excess CO2 and replenish its supply of O2

what is the functional blood supply of the lungs supplied by?

the bronchial arteries

fetal circulation

all gaseous exchanges occur through the placenta

what are two organs bypassed by the circulatory system in the fetus?

liver and lungs

hepatic portal circulation

drain the digestive viscera, spleen, and pancreas and deliver this blood to liver for processing

liver

maintains proper sugar, fatty acid, and amino acid concentrations in the blood (HPS ensures that these substances pass through liver before entering the systemic circulation)

cardiac cycle

equivalent to one heartbeat, during which both atria and ventricles contract than relax
1. ventricular filling (passive)
1. ventricular filling with atrial contraction
2. isovolumetric contraction
3. ventricular ejection
4. isovolumetric relaxation

ventricular filling

when atrial pressure is greater than ventricular pressure, the AV valves are forced open and blood flows passively into the atria and on through tho the ventricles

atrial contraction

complete the filling on the ventricles

isovolumetric contraction

the contraction of the ventricles begins and ventricular pressure increases, closing the AV valves

ventricular ejection

- ventricular pressure continues to rise
- when the pressure in the ventricles exceeds the pressure in the great vessels exiting the heart, the SL valves open and blood is ejected

isovolumetric relaxation

- the ventricles relax, decreasing the pressure
- SL valves close
- dicrotic notch is the result of a pressure fluctuation that occurs when the aortic valve snaps shut

lub sound

closure of the AV valves at the beginning of ventricular systole

dub sound

closure of the SL valves and corresponds to the end of ventricular systole

murmurs

- abnormal heart sound
- often indicate valvular problems

pulse

- alternating surges of pressure in an artery that occur with each contraction and relaxation of the left ventricle
- normally 70 - 76 bpm at rest

superficial pulse points

- superficial temporal artery
- facial artery
- common carotid artery
- brachial artery
- radial artery
- femoral artery
- popliteal artery
- posterior tibial artery
- dorsalis pedis artery

blood pressure

- the pressure the blood exerts against any unit area of the blood vessel walls (reported in mmHg)
- BP \= CO x TPR

systolic pressure

pressure in the arteries at the peak of ventricular contraction

diastolic pressure

the pressure during ventricular relaxation

normal blood pressure

systolic less than 120 AND diastolic less than 80

elevated blood pressure

systolic is 120-129 AND diastolic is less than 80

stage 1 hypertension

systolic is 130-139 OR diastolic is 80-89

stage 2 hypertension

systolic is 140 or higher OR diastolic is 90 or higher

end diastolic volume

blood in ventricle at the end of diastole

stroke volume

amount of blood ejected from each ventricle in one heart beat

total peripheral resistance

amount of force exerted on blood by vasculature

cardiac output

- the amount of blood pumped by the heart in one minute
- CO \= SV x HR

mean arterial pressure

- average pressure in patient's arteries during one cardiac cycle
- MAP \= (SBP + 2DBP)/3

pulse pressure

- difference between systolic and diastolic blood pressure
- PP \= SBP - DBP

heart rate

- number of heart beats in one minute
- HR \= 60 sec/ heart beat duration

heart beat duration

60 sec/heart rate

how to measure blood pressure with a sphygmomanometer

place blood pressure cuff on upper left arm, inflate until circulation is cut off, slowly release until first sound is heart (systolic pressure), continue to release until sound disappears (diastolic)

A patient visits their doctor and and learns that their blood pressure is 128mmHg/91mmHg. What is their mean arterial pressure?

103.33

A patient visits their doctor and and learns that their blood pressure is 103mmHg/72mmHg. What is their mean arterial pressure?

82.33

A patient visits their doctor and and learns that their blood pressure is 147mmHg/92mmHg. What is their pulse pressure?

55 mmHg

During a lab exercise, you determine that your lab partner has a heart rate of 68 bpm. How long does their average heart beat last (in seconds)?

0.88 seconds

pulmonary ventilation

movement of air into and out of the lungs that allows the gases to be continuously changed and refreshed (AKA breathing)

external respiration

gas exchange between the blood and the air-filled chambers of the lungs

internal respiration

exchange of gases between systemic blood and tissue cells

upper respiratory system

includes the external nose, nasal cavity, pharynx, and paranasal sinuses

external nose

nostrils provide an entrance for air into the respiratory system

nasal cavity

- composed of pseudostratfied ciliated columnar epithelium
- filters, warms, and moistens incoming air
- resonance chamber for voice production

nasal vestibule

filters coarse particles from the air

nasal septum

divides the nasal cavity into left and right sides

nasal conchae

- increase surface area of the mucosa
- enhance air turbulence
- aids in trapping large particles in the mucus

posterior nasal aperatures

provide an exit for air into the nasopharynx

nasopharynx

- provide passage for air from nasal cavity
- tonsils in this region protect against pathogens
- lined with psuedostratfied ciliated columnar epithelium

oropharynx

- provides for the passage of air and swallowed food
- tonsils in this region protect against pathogens
- lined with stratified squamous epithelium

laryngopharynx

- provides for the passage of air and swallowed foods
- lined with stratified squamous epithelium

pharyngotymapnic tube

allows the middle ear pressure to equalize with the atmospheric pressure

paranasal sinuses

- act as resonance chambers for speech
- warm and moisten incoming air
- lined with psuedostratifed ciliated columnar epithelium

lower respiratory system

includes the larynx, trachea, bronchi, and lungs

larynx

- air passageway
- prevents food from entering lower respiratory tract
- responsible for voice production

epiglottis

- forms a lid over the larynx during swallowing
- made of elastic cartilage

vocal folds (true vocal cords)

vibrate with expired air for sound production

vestibular folds (falso vocal folds)

protect the vocal folds and help to close the glotttis when we swallow

glottis

slitlike passageway between the vocal folds

root of lung

connects each lung to the mediastinum

hilum

an indentation of the lung where root enters/leaves

costal surface

anterior, lateral, and posterior lung surfaces in close contact with the ribs

cardiac notch

concavity on the medial surface of the left lung

pleura

a double-layered sac of serous membrane

parietal pleura

outer layer of the pleura, attached to the thoracic alls and diaphragm

visceral pleura

inner layer of pleura, covers the lung tissue

pleural cavity

- found in between visceral and parietal pleura
- filled with pleural fluid (allows lungs to glide without friction)

respiratory membrane

- AKA blood air barrier
- formed by the alveolar and capillary walls and their fused basement membranes

inspiration

- external intercostals and diaphragm contract
- intrapulmonary volume increases
- decreased air pressure inside the lungs --\> gas then expand to fill the space, creating a vacuum that causes air to flow into the lungs

expiration

- inspiratory muscles relax
- elastic lung tissue recoils
- decrease in intrapulmonary volume
- gas molecules in the lungs are forced closer together, raising intrapulmonary pressure, causing gases to flow out of lungs to equalize pressure with atmosphere

tidal volume

amount of air inhaled or exhaled with each breath under resting conditions (500mL)

inspiratory reserve volume (IRV)

amount of air that can be forcefully inhaled after a normal tidal volume inspiration (3100mL)

expiratory reserve volume (ERV)

amount of air that can be forcefully exhaled after a normal tidal volume expiration (1200mL)

residual volume (RV)

amount of air remaining in the lungs after a forced expiration (1200mL)

total lung capacity (TLC)

maximum amount of air contained in lungs after a maximum inspiratory effort (TLC \= TV + IRV + ERV + RV)

vital capacity (VC)

maximum amount of air that can be expired after a maximum inspiratory effort (VC \= TV + IRV + ERV)

inspiratory capacity (IC)

maximum amount of air that can be inspired after a normal tidal volume of expiration (IC \= TV + IRV)

functional residual capacity

volume of air remaining in the lungs after a normal tidal volume expiration (FRC \= ERV + RV)

forced vital capacity (FVC)

measures the amount of gas expelled when the subject takes the deepest possible breath and then exhales forcefully and rapidly

forced expiratory volume (FEV)

percentage of vital capacity that is exhaled during specific time intervals

where are the neural centers that control respiratory rhythm and maintain respiratory rate?

medulla and pons

pH

- 7.4
- must be relatively constant for the cells of the body to function optimally

carbonic acid

formed when CO2 combines with water

carbonic anhydrase

catalyzes reaction of H2O and CO2 to form carbonic acid

bicarbonate ion

result of dissociation of carbonic acid

chloride shift

Cl- moves into the cell when HCO3- leaves

carbonic acid-bicarbonate buffer system

stabilizes blood pH

obstructive respiratory diseases

- characterized by increased resistance in the airways
- normal vital capacity but decreased rate of air flow due to bronchoconstriction
- ex: asthma, chronic bronchitis

restrictive respiratory diseases

- lung capacity declines
- ex: polio, tuberculosis

hyperventilation

- decreased carbonic acid production in RBCs
- LESS H+ produced by dissociation
- results in respiratory alkalosis (higher than normal pH)

hypoventilation

- CO2 is not properly removed from body through respiration
- increased carbonic acid production [CO2 + H2O]
- MORE H+ produced by dissociation
- results in respiratory acidosis (lower than normal pH)