Transcript 7cardio
Circulatory system + the
blood
Chapters 5 and 6
Circulatory system
PREVENTS CELLS FROM
SUFFOCATING
BRINGS CELLS OXYGEN AND
NUTRIENTS
Also called the cardiovascular system
Pathway of blood
PATHWAYS
HEART- PUMPS BLOOD
ARTERIES- CARRY BLOOD AWAY
FROM THE HEART
VEINS- CARRY BLOOD TOWARD THE
HEART
CAPILLARIES- TINY VESSELS THAT
REACH SINGLE CELLS- THE SITE
WHERE EXCHANGE OCCURS
ARTERIES
WALL- have 3 LAYERS
INNER- simple squamous epithelium +
connective tissue= endothelium
Middle- smooth muscle
Outer- loose and fibrous connective
tissue
Arterioles- tiny arteries
Capillaries
Nourish individual cells
can be closed when muscles in
precapillary sphincter are contracted
an arteriovenous shunt is a vessel
allows the blood to bypass the
capillaries and move on to a venule
while the precapillary sphincter is closed
Veins
Venules- tiny veins that drain capillary
beds
3 layers, but less muscle and connective
tissue
Have one way valves to prevent blood
from staying in the legs
Vein walls can expand- 70% of all the
blood is in the veins
One way valves in veins
Heart
Cone shaped, fist sized
Myocardium- the cardiac muscle
Pericardium- the thick sac around the
heart
Septum- the internal wall that separates
the right and left halves
Upper 2 chambers- atria
Lower 2- ventricles
Valves
Chordae tendineae- strings that prevent
one way valves from opening backwards
Atrioventricular valves- separate upper
and lower chambers
Right- tricuspid
Left- bicuspid or mitral
Semilumar valves- downstream of
ventricles
pulmonary- right aortic- left
Heart
Major vessels
Right half source of blood- from superior
and inferior vena cavae
Right blood output- to Pulmonary
arteries
Left blood input- from pulmonary veins
Left output- to Aorta
HEART
RIGHT SIDE- PUMPS OXYGEN POOR
BLOOD FROM BODY (VENA CAVA)
TO LUNGS (PULMONARY ARTERY)
LEFT SIDE- PUMPS OXYGEN RICH
BLOOD FROM LUNGS (PULMONARY
VEIN) TO THE REST OF THE BODY
(AORTA)
The Left side works harder
Path of blood through the heart
Cardiac cycle
Systole- period of muscle contraction
Diastole- resting period
Lub dub- sound of heart valves slamming shut
Murmur- caused by leaky valves
SA node- the heart’s pacemaker- located on the right
atrium, creates the electrical impulse
AV node- below right atrium- electrical impulse passes
through on its way to
Perkinje fibers- conducts the impulses to the muscle
cells that cause contraction of ventricles
Control of heart rate
1 Medulla oblongata- nerve impulses from
brain stem
2. Endocrine hormones from adrenal
glands- epinephrine and nor epinephrine
Defibrillation- an electrical shock to
reestablish ventricular rhythm given to
persons with heart problems
HEART ATTACK
BLOCKAGE OF A CORONARY
ARTERY which supplies the heart
muscle with oxygen and nutrients
PART TO HEART MUSCLE
SUFFOCATES
IF ENOUGH MUSCLE TISSUE STOPS
WORKING THEN THE HEART CAN’T
PUMP BLOOD (massive heart attack)
Other Problems/Treatments
Aneurysm- ballooning of weakened artery, can
burst and cause massive internal bleeding
Treatments for clogged vessels
Nitroglycerine- dilates blood vessels
Clot dissolving drugs- to treat heart attack
Angioplasty- balloon inflated inside a partially
clogged artery to expand it
Plaque in blood vessel
Coronary bypass
BLOOD PRESSURE
THE FORCE THAT BLOOD EXERTS
AGAINST THE WALLS OF OUR
BLOOD VESSELS
CONTRACTION OF VENTRICLES=
HIGH PRESSURE- SYSTOLE
PRESSURE DROPS MOMENTARILYwhen the heart relaxes- DIASTOLE
BLOOD PRESSURE
SYSTOLE/DIASTOLE
MEASURED WITH A STETHOSCOPE
AND PRESSURIZED CUFF
CUFF CUTS OFF BLOOD AT A HIGH
ENOUGH PRESSURE
SYSTOLIC- 110-140 = NORMAL
BELOW 100- LOW
HYPERTENSION- 140/90 or greater
Blood pressure
Arteries during blood pressure
check
Other Problems
Hypertension= High blood pressure
Atheriosclerosis- cholesterol under
endothelium of arteries
Blood clots may form on the irregular
artery walls
Thrombus- attached clot- embolus- free
clot which is moving through the vessels
Stroke- burst or blockage of brain arteriole
Veins
Weak one way valves- causes swelled
veins (spider veins and varicose veinsusually in the legs/feet)
Hemorrhoids- swelled veins of rectum
Phlebitis- inflammation of veins