Transcript Chap 18 – Blood Vessels

Chap 18 –
Blood Vessels
Homework: Read Chap 18. Review
notes from class.
Learning Objectives:
1. Describe the structure of blood vessels walls.
2. Differentiate between vasoconstriction and vasodilation.
3. Explain blood pressure and factors that influence blood
pressure as well as elevation of blood pressure.
4. Compare and contrast the structures and functions of
the various blood vessels.
Critical Situation: Aorta Aneurism
View a life-threatening scenario:
http://www.sjhlex.org/documents/HeartAw
are%20Animations/animAAA.htm
Cool fact: The blood vessels of an adult human stretch for about
60,000 miles through the internal landscape of the body!
Discussion
• What are the three major types of blood
vessels?
Artery and Vein Structure, pg 627
Arteries and
veins are
composed of
three tunics:
1. tunica
__________
2. tunica
_________
3. tunica
_________
Think-Pair-Share
Instructions:
1. Quickly pair with a partner.
2. Review Table 18.1 Summary of Blood
Vessel Anatomy and outline the following
in your notes:
a) The 6 types of vessels in the body
b) What’s the smallest of the 6 vessels?
3. Be prepared to share with the class.
Elastic Conducting Arteries
• Thick-walled arteries _____ ____ _____;
the aorta and its major branches
– Large lumen allow low-resistance conduction
of blood
– Contain elastin in all three _______
– Withstand and smooth out large blood
pressure _________
– Allow blood to flow fairly continuously through
the body
Muscular Arteries and Arterioles
• Muscular arteries – ______ to elastic
arteries; deliver blood to ____ _______
– Have thick tunica media with more smooth
muscle and less elastic tissue
– Active in vasoconstriction
• Arterioles – ________ arteries; lead to
capillary beds
– Control flow into capillary beds via
vasodilation and constriction
Capillaries
• Capillaries are the ______ blood vessels
– Walls consisting of a thin tunica interna, one
____ thick
– Allow only a _____ RBC to pass at a time
• There are three structural types of
capillaries: continuous, fenestrated, and
sinusoids
Capillary Beds
• A microcirculation of interwoven networks
of capillaries
Venous System: Venules
• Are formed when capillary beds ______
– Allow fluids and WBCs to pass from the
bloodstream to ________
• Postcapillary venules – smallest venules,
composed of endothelium
• Large venules have one or two layers of
________ muscle (tunica media)
Veins
• Veins have much _____ blood pressure and _______ walls
than arteries
• To return blood to the heart, veins have special adaptations
– _______ (resembling semilunar heart valves), which
prevent backflow of blood
• Veins are:
– Formed when venules converge
– Composed of _______ tunics, with a thin tunica media
and a thick tunica externa consisting of collagen fibers
and elastic networks
– Blood reservoirs that contain __% of the blood supply
Review
1. What is the inner-most structural layer of an
artery or vein?
2. What’s the main distinction between elastic
arteries and muscular arteries?
3. What’s the smallest of the arteries?
Discussion
• What is Blood Pressure?
http://health.howstuffworks.com/adam-200079.htm
Understanding Blood Pressure
• ________ pressure (top number) – pressure
exerted on arterial walls when ventricles contract
• _______ pressure (bottom number) – the
pressure when the heart relaxes between beats
For example: 118 / 76
Blood pressure below 120 over 80 mmHg (millimeters of mercury) is
considered optimal for adults.
A blood pressure reading of 140 over 90 or higher is considered elevated
(high).
Maintaining Blood Pressure
• Maintaining blood pressure requires:
– Cooperation of the _____, blood _______,
and _______
– Supervision of the _______
Chemicals That Increase Blood Pressure
• Adrenal medulla hormones – ___________ and
_________ increase blood pressure
Antidiuretic hormone (ADH) – causes intense
vasoconstriction in cases of extremely ____ BP
Angiotensin II – kidney release of renin generates
angiotensin II, which causes intense ___________
Endothelium-derived factors – endothelin and
prostaglandin-derived growth factor (PDGF) are
both vasoconstrictors
Chemicals That Decrease Blood
Pressure
• Atrial natriuretic peptide (ANP) – causes
blood _______ and ______ to decline
Inflammatory chemicals – ___________,
prostacyclin, and kinins are potent
vasodilators
Nitric oxide (NO) – has brief but potent
vasodilator effects
_________– causes BP to drop by inhibiting
ADH
Kidney Action and Blood Pressure
• Kidneys act directly and indirectly to
maintain long-term _____ _________
– Increased BP stimulates the kidneys to
eliminate ______, thus reducing BP
– Decreased BP stimulates the kidneys to
increase blood volume and BP
Review
1. How does alcohol effect blood pressure?
2. What effect does epinephrine have on
blood pressure?
3. In a blood pressure reading such as
120/80, the top number is “systolic”. What
does that represent?
Circulatory Shock
• ___________ shock – results from largescale blood loss (i.e., acute hemorrhage,
severe burns)
________ shock – normal blood volume but
circulation is poor as a result of abnomral
expansion of the vascular vessels (i.e.,
severe sunburn
___________ shock – pump failure; heart is
inefficient (i.e., resulting from multiple heart
attacks)