Transcript I Blood Vessels - Belle Vernon Area School District

1. Name the layers of the blood vessels.
2. How many cells thick are the capillaries and
why?
3. Compare and contrast the structure of veins
and arteries.
1. Name the major arteries of the following
areas: head, arms, legs.
2. How are the precapillay sphincter muscles
controlled?
3. What is the difference between hydrostatic
pressure & osmotic pressure?
4. If someone’s blood pressure is 140/80, what
is their pulse pressure?
• What do the two numbers represent in your
blood pressure?
• What is an example of a normal blood
pressure?
• Which blood vessels have the highest and
lowest blood pressure? Why?
• Explain how baroreceptors and
chemoreceptors help maintain normal blood
pressure.
Blood Vessel and Circulation
Functions
1. Carry Blood
2. Exchange of nutrients
3. Transport
4. Regulate blood pressure
5. Direct blood flow
I Blood Vessels - Forms a closed circulatory
system (Arteries ->Capillaries ->Veins)
Made up of three layers
a. Lumen - space for the flow of blood.
b. Tunica Intima - inner lining.
c. Tunica Media - smooth muscle, contractibility.
d. Tunica Adventitia – anchoring
A. Arteries - Carries blood away from the
heart
Strong & Elastic
1. Elastic Arteries – Largest in
diameter.
Mainly elastic
2. Muscular arteries – medium sized
and small diameter.
Mainly smooth muscle
3. Distributing arteries –
vasoconstriction Vasomotor fibers of the
sympathetic (autonomic)
.
vasodilatation - nerve
impulse is inhibited muscle relaxes & elastic
fibers recoils.
4. Small arteries
5. Arterioles - 0.5 mm in diameter
B. Capillaries - Thin wall blood
vessels that permit exchanges of
material.
1. Connect arteries to
veins
2. 0.01 mm in diameter lumen
3. Can only fit 1 RBC at a
time.
4. Form capillary beds or
networks.
• Thoroughfare channels connect arterioles directly to
veins
• True Capillaries - 10-100 per
bed
Precapillary Sphincter - valve that
regulates flow of blood into those
capillaries.
C. Veins - Carries blood toward the heart
1. Thinner & collapse.
2. Holds 65% of the body’s blood.
3. Low blood pressure, too low to be
pumped back to the heart.
1 way valves
Body movement Skeletal contraction,
breathing.
4. Made up of three layers - same as
arteries
5. Varicose veins overstretched veins from
blood pooling , hemorrhoids.
6. Venules – thinner versions
of veins
Blood flow
through
the
circulatory
system
Arteries
Major arteries of the body
Veins
Major veins of the body
II. Blood Pressure - force exerted by blood
against the inner walls of vessels
A. Influenced by:
Cardiac Output
Blood Volume
Peripheral Resistance which is
regulated by nerve, kidneys,
hormones.
B. Moves from regions of higher pressure
to lower pressure
Systolic - Peak pressure - 120 mmHg
Diastolic - Resting - 70 - 80 mmHg
Sphygmomanometer - measures blood
pressure.
Stethoscope – Hearing
Korotkoff - tapping sound sounds
C. Pulse - rhythmic expanding & recoiling of an arterial
wall
Average
Adult 70 - 90 bpm
Child 80 - 140 bpm
tachycardia - heart rate is above 100 bpm at rest
bradycardia - heart rate is lower than 60 bpm at rest
Auscultatory Method
Sphygmomanometer
Stethoscope
Korotkoff sounds
D. Blood Pressure
Pulse Pressure
Pulse pressure – the difference between
systolic & diastolic pressure.
120/80 – 40 pulse pressure.
Factors effecting pulse pressure.
Activity - increase
Arteriosclerosis- decrease
III Capillary Exchange
10 Billion capillaries
Materials (gases, nutrients) move
across capillary walls by
diffusion, osmosis, facilitated
diffusion & active transport.
Small amount of fluid also moves
across the capillary walls:
Hydrostatic pressure - blood
pressure within the capillaries
Osmotic pressure - movement of
fluid from cells to plasma
90% reabsorbed back into the blood
10% returned back by the lymphatic
system
IV. Regulation of blood pressure - regulation of
steady pressure is important.
A. Nervous Control - Adjusts cardiac output
& peripheral resistant by autonomic fibers to
the SA node & reflex center (vasomotor
center in the medulla oblongata & pons).
1. Peripheral resistance - control by activity
of vasomotor between the smooth
muscle & reflex center of Medulla
(Vasomotor tone, increases =
constriction).
2. Control of vasomotor center (MAP)
Map = CO X PR
a. Baroreceptors – located in major
vessels above the heart & detect
changes in the blood pressure.
Moment to moment control
b. Chemoreceptors - Sensitive to changes
in oxygen levels or hydrogen ions (pH)
level.
carotid bodies – carotid sinus
aorta bodies - aorta
B. Hormone Control
1. Epinephrine & norepinephrine
a. Activated by the sympathetic division of the
autonomic division
b. Fight or flight response - times of stress
c. Epinephrine - increases cardiac output
d. Norepinephrine - increases peripheral
resistance
2. Atrial natriuretic factor - secreted by the atria of the heart
a. Reduces blood volume
b. Stimulates the kidney to secrete more sodium
& water
c. Less water
d. Drop in blood volume
3. Antidiuretic hormone (vasopressin)
a. Produced by the hypothalamus
b. Stimulates the kidneys to increase water absorbtion
c. Increase in blood volume
C. Kidney Control - Main mechanism of long term control
1 High blood pressure - excretes more water
Low blood pressure - conserve more water
2. Release of special chemicals
a. Reduced blood flow causes renin to be released by the kidney and
causes the formation of Angiotensin I.
Angiotensin I + angiotensin-converting enzyme makes
angiotension II = vasoconstrictor.
b. Angiotensin II - Aldosterone release by the adrenal glands to stimulate
the reabsorbtion of sodium & water.
V. Cardiovascular diseases
A.
Aneurysm - formation of a sac
within the heart or blood
vessels due to stretching
B. Arteriosclerosis - Loss of
elasticity in arterial walls
C. Atherosclerosis - narrow of
arteries by plaque build up
Cardiovascular diseases
Cardiovascular diseases
D. Congestive heart failure - failure of the heart to pump blood to the
body tissues
E. Heart Block - Failure of the SA or AV. to generate impulses
F. Heart fibrillation - Heart beats at a irregular pace
G. Heart flutter - heart race up to 300 bpm
H. Hypertension - elevated blood pressure
I. Murmur - Leaking of blood through a closed valve
J. Myocarditis - infection of the heart muscle
K. Pericarditis - Infection of the pericardial sac which results in thicken
or scarring
Circulation
II. Circulatory Pathways
A. Pulmonary Circulation - Heart
->Lungs -> Heart
Drop off CO2 & pick up oxygen
1. Pulmonary artery
2. Pulmonary vein
B. Systemic Circulation - Heart ->Body ->Heart
Nutrients to cells & remove metabolic wastes
Transports: gases, nutrients, wastes, blood cells, proteins (enzymes),
hormones
1. Major Arteries
a. Carotid Artery (internal & external)
b. Brachiocephalic artery (arms)
c. Subclavian (shoulder)
d. Aorta
e. Common iliac artery
f. renal artery kidney
g. Axillary (armpit)
h. Brachail artery
i. Radial artery
J. ulnar artery
k. femoral
l. posterior/anterior tibial artert
m. fibular artery
2. Major Veins
a. Jugular veins (internal & external)
b. Right & Left Brachiocephalic veins
c. Inferior & superior vena cava
d. Common Iliac vein
e. Subclavin vein
f. renal vein kidney
g. Axillary (armpit)
h. Brachail vein
i. Radial vein
J. ulnar vein
k. femoral vein
l. posterior/anterior tibial vein
m. fibular vein
n. hepatic portal vein
Circulation