Lab Practical #2

Arteries: Elastic

• Close to the heart

• Large

• Most expandable

Arteries: Muscular

• medium sized

• named arteries in the body

Arteries: Arterioles

• smallest

• “Resistance vessels”

Blood vessels: Capillaries

• provide exchange of materials in tissues

• narrowest vessel

• one cell layer - endothelium

Blood vessels: Veins

• 65% of blood volume is in the veins

• low pressure because of thin walls and large lumens

veins draining into the vena cavae

• Draining the arm:

  • radial and ulnar veins - brachial vein - axillary vein

• Subclavian vein recieves:

  • Venous blood from axillary vein

  • Venous blood from skin and muscles of head and neck via external jugular vein

• Internal jugular vein drains the dural sinuses of brain

• Left and right brachiocephalic veins recieve veniys blood from:

  • subclavian veins

  • vertebral veins

  • internal jugular veins

Path of blood through circulatory system

Heart - large arteries - medium arteries - arterioles - capillary beds - venules - mediium veins - large veins - heart

Pulmonary Circulation

• Capillary beds exchange around alveoli permit gas exchange (CO2 for O2)

• Nourishing blood supply for the lungs provided by bronchial arteries, not pulmonary circulation

Hepatic portal system

• veins drain the:

  • digestive system

  • spleen

  • pancreas

• major veins

  • inferior and superior mesenteric veins

  • splenic vein

  • left gastric vein

• Capillary beds of digestive system absorb nutrients

• liver helps maintain proper glucose, fat and protein cconcentrations

• Liver filters toxins

• Blood drains into hepatic veins as it leaves liver

Fetal circulation

• Fetus receives exchanges of gases, nutrients, and wastes through the placenta

• Umbilical cord vessels:

  • umbilical vein - carries blood rish in nutrients and oxygen to fetus

  • umbilical arteries (2) - carry carbon dioxide from fetus to placenta

• Blood flow bypasses liver through the ductus venosus and enters interior vena cava

• Blood flow bypasses the lungs

  • blood enters right atrium and is shunted to left atrium through foramen ovale

  • ductous arteriosus connects aorta and pulmonary trunk

Cerebral arterial circle

• Circle of Willis - protects brain blood supplly if one artery is blocked or narrowed. It reroutes blood

• Internal carotid arteries divide into anterior and middle cerebral arteries

  • supply most of cerebrum

• Vertebral arteries join once within the skull to form basilar artery

• posterior cerebral arteries form from the division of the basilar artery

Phases of cardiac cycle

• atrial diastole - blood delivered into atria via veins

  • 80% of blood flows passively into ventricles

• artrial systole

  • last 20%of blood left in atria delivered to ventricles by atrial systole

• ventricular systole

  • ventricular contractions - closing the AV valves

  • ejection phase - blood pumped into great arteries

• ventricular diastole

Pulse

• Surges of pressure in arteries - heart rate

• Normal range for resting: 60-100 bpm

• Average resting heart rate: 70-76 bpm

• 60 sec / heart beat duration

Blood pressure

• pressure exerted against walls of arteries

• systolic blood pressure: pressure against walls of arteries during ventricular systole

• diastolic blood pressure: pressure against the arterial wall during ventricular diastole

• SDP/DBP mmHg

Calculating overall blood pressure

CO = SV x HR

BP = CO x TPR

• CO - amount of blood pumped by the heart in one minute

• SV - amount of blood pumped by left ventricle during one contraction

• TPR - amount of force exerted on circulating blood by the vasculature

Pulse pressure

SBP - DBP

MAP

DBP + (pulse pressure/3)

or

(SBP + (2 x DBP)) / 3

Heart sounds

1st sound: lub - closure of AV valves

2nd sound: dub - closure of SL valves

Heart murmur

• abnormal heart sound

• indicated a defect in one of the valves

Upper division:

• structures found in head and neck

  • external nose, nasal cavity, paranasal cavity and pharynx

• Functions

  • dilters, warms and moistens incoming air

  • chamber for voice

  • smell

Upper division: pharynx

• connects nasal and oral cavities to larynx and esophogus

• Nasopharynx

  • respiration

• Oropharynx

  • respiratory and digestive functions

• Laryngopharynx

  • respiratory and digestive

Lower divison: larynx

• prevents food/fluid from entering lungs

• allows passage of air and produces sound

• composed of cartiaginous and membranous structures

Cartilages of larynx

• thyroid (Adams apple)

• cricoid cartilage

• Arytenoid carteliage - anchors vocal folds

• epiglottis - closes opening of trachea during swallowing

Lower division: trachea

• walls reinforced with C-rings of hyaline cartilage

• lined wit pseudostratified ciliated columnar epithelium

Lower division: bronchi

• branching respiratory tubes

• divides into right and left plmonary bronchi

Lower division: lungs

• soft: spongy organs

• Cardiac notch

  • concavity or left lung that provides space for the heart

  • left lung - 2 lobes

  • right lung - 3 lobes

Plurae of lungs

pariteal pleura - outer layer that attach thoracic walls and diaphragm

visceral pleura - inner layer, cover external surface of lung

process of respiration

1) pulmonary ventilation

2) external respiration - gas exchange

3) transport of respiratory gasses to tissues

internal respiration - gas exchange between blood and tissues

mechanics of respiration

inspiration - air moves to lungs

• thoracic cavity increase in size

• intrapulmonary volume increases

• intrapulmonary volume decreases

• air flows to area of low pressure (in lungs)

expiration - air moves out of lungs

• thoracic cavity decreases in size

• intrapulmonary volume decreases

• intrapulmonary pressure increases

• air flows to area of low pressure (out of lungs)

bronchial sounds

produced by air rushing through the large respiratory passageways

abornmal sounds - wheezing, rales

• diseased tissue, mucus or pus

Obstructive diseases

• increased resistance in airways

• normal vital capcity but decrease rate of air flow due to bronchoconstriction

• asthma, chronic bronchitis

Restrictive disease

• lung capacity declines

• Polio, tuberculosis

Carbonic acid-bicardbonate buffer systems

• Arterial blood pH is maintained at 7.4 by buffer system

• CO2 diffuses into blood from tissues

• in red blood cells CO2 combines with H20 to form H2Co3 - carbonic acid

• H2CO3 breaks down into HCO3 - biocarbonate ion and H+

• H+ are neutralized by attaching onto hemoglobin

• HCO3 moves into plasma

How buffer system maintains blood pH

• If pH decreases - increase in H+

• If pH increases - decrease in H+

Hyperventilation

• fast deep breathing

• decreased carbonic acid and H+

• results in alkalosis - higher than normal pH

Hypoventilation

• slow or shallow breathing

• increased carbonic acid and H+

• results in respirator acidosis - lower than normal pH

Tidal volume

• amount of air inhaled or exhaled in a normal breath

ERV

• expiratory reserve volume - max amount of air exhaled after normal breath

Vena cava

Aorta

trachea

Pseudostratified ciliated epithelium

healthy lung