BIOL125 Lecture Notes - Lecture 8: Sine Wave, Tunica Media, Varicose Veins

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BIOL week 8 LC  Anatomy of the Vascular System

The CVS: Blood Vessels

- The blood vessels of the body form a closed delivery system that begins and ends at

the heart (blood cannot escape – remains in the circulation)

- Blood vessels transport hormones, oxygen (as haemoglobin), carbon dioxide (as

bicarbonate ions)

- Vena cava is largest vein – transports blood back to the heart and then to the lungs

- Functions:

oDistribution of blood

oExchange of materials at the capillaries

oReturn of blood to the heart

Types of Blood Vessels

- Arteries  carry blood away from heart; large amount of smooth muscle to maintain

pressure; branch repeatedly into smaller arteries then into arterioles

- Arterioles  carry blood to capillary beds; contain smooth muscle to maintain

pressure

- Capillaries  site of diffusion of gases, nutrients and wastes between blood and

interstitial fluid (ISF); leads into venules; have only 1 layer of endothelia cells

- Venules  larger veins direct blood into small veins

- Veins  direct blood back to the heart; join together to flow into superior and inferior

vena cava

- Arteries and veins supplying same region lie side by side eg. Femoral artery and vein

- The nervous system, through vasoconstriction and vasodilation, can control smooth

muscle in blood vessel wall

- Aorta transports blood from the left ventricle  contains largest amount of elastin

fibres, allowing contraction

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- Fenestrated capillary  have pores through which more materials can come through

– more permeable than continuous capillary

- Sinusoid capillary has most permeability due to larger pores

- Tunica media is where blood innervates artery; responsible for lumen size

- Function of tuncia externa is to support and protect

- Walls of the arteries are much thicker

- Lumen size is wider in the veins

- Arteries can expand and recoil passively

- High pressure system for arteries and low pressure system for veins

Structure of Blood Vessel Walls

- Walls of arteries and veins have three layers: tunica intima (inner), tunica media

(middle), and tunica externa (outer)

- Tunica intima  endothelium lining and surrounding connective tissue with variable

number of elastic fibres; arteries also have thick internal elastic membrane in outer

part

- Tunica media  thickest layer in most arteries; concentric smooth muscle sheets in

loose connective tissue framework; has thin band of elastic fibres beneath externa

layer ie. External elastic membrane

- Tunica externa  connective tissue sheath; in arteries has collagen fibres and

scattered bands of elastin fibres; generally thickest layer in veins; anchors blood

vessel into surrounding tissue

Differences between arteries and veins

- Vessel wall  walls of arteries are thicker than those of veins. Tunica media of

arteries has more smooth muscle and elastic fibres to resist arterial pressure as

ventricles pump blood

- Vessel lumen  when not opposed by blood pressure (BP), elastic fibres in arterial

walls recoil reducing size of lumen; lumen keeps round shape but can narrow due

vasoconstriction and vasodilation, controlling blood flow through circulatory system.

Veins are capacitance vessels (can expand to allow more blood through); veins have

wide lumens

- Vessel lining  arterial endothelium cannot contract – pleated/folded appearance in

constricted artery. Veins do not have folds (contraction rarely required in venous

tissue)

In the veins, blood flow is assisted by the function of skeletal muscles - valves

- Arteries retain their cylindrical shape, but veins may collapse

- Arteries are more resilient: may be stretched out of shape then return to normal

- Veins cannot tolerate much distortion before tearing or collapsing

- Amount of elastic fibres, collagen and smooth muscle is greater in arteries than in

veins

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Document Summary

Biol week 8 lc anatomy of the vascular system. The blood vessels of the body form a closed delivery system that begins and ends at the heart (blood cannot escape remains in the circulation) Blood vessels transport hormones, oxygen (as haemoglobin), carbon dioxide (as bicarbonate ions) Vena cava is largest vein transports blood back to the heart and then to the lungs. Functions: distribution of blood, exchange of materials at the capillaries, return of blood to the heart. Arteries carry blood away from heart; large amount of smooth muscle to maintain pressure; branch repeatedly into smaller arteries then into arterioles. Arterioles carry blood to capillary beds; contain smooth muscle to maintain pressure. Capillaries site of diffusion of gases, nutrients and wastes between blood and interstitial fluid (isf); leads into venules; have only 1 layer of endothelia cells. Venules larger veins direct blood into small veins.

Related Questions

1. Which of the following is the correct sequence of bloodflow?

a. heart --> atery --> arteriole --> capillary -->vein --> venule --> heart

b. heart --> vein --> venule --> capillary -->arteriole --> artery --> heart

c. heart --> artery --> arteriole --> capillary -->venule --> vein --> heart

d. heart --> artery --> venule --> capillary -->arteriole --> vein --> heart

e. heart--> artery --> capillary --> arteriole -->venule --> vein --> heart

2. What are the functions of the elastic fibers that are foundin the walls of ateries? (there may be more than one answer)

Select one or more:

a. they allow the artery to stretch and then recoil back to itsoriginal shape as blood is forcegully pumped from the heart intothe arteries

b. they allow arteries to lengthen as the volume of blood in thearteries increase

c. they help maintain a steady blood pressure during thedifferent phases of heart contraction

d. they smooth out the walls of the arteries to preventturbulent blood flow

3. Which of the following are functions of the lymphatic system?(there may be more than one answer)

Select one or more:

a. help fight infections and cancer

b. allows excess interstitial fluid (fluid found between thecells in your tissues) to get dumped back into your blood

c. brings large molecules from fat digestion into thebloodstream so that they can be processed and stored

d. all of the above are functions of the lymphatic system

4. Which of the following blood vessels bring newly oxygenatedblood from the blood vessels in the lungs back to the heart so thatthe heart can pump it to the rest of the body?

Select one:

a. aorta

b. inferior vena cava

c. pulmonary vein

d. pulmonary artery

5. Which of the following mechanisms help blood fight gravity sothat, for instance, it can return from blood vessels in your feetback into your heart? (there may be more than one answer)

Select one or more:

a. breathing allows the pressure in your chest to decrease andallow blood to flow up towards your heart

b. as you walk, the skeletal muscles in your legs contract andsqueeze the veins; since veins have valves, blood flows up anddoesn't backflow back down

c. the force of blood flowing out of the heart and into thearteries pushes all of the blood along, causing blood to return tothe heart

d. precapillary sphincters open to allow blood to flow backtowards the heart

6. The tricuspid and bicuspid/mitral valves prevent backflow ofblood from the atria into the ventricles.

Select one:

True

False

7. The following sequence represents the correct order of bloodflow through the heart:

inferior and superior vena cava --> right atrium --> rightventricle --> pulmonary artery --> lungs --> pulmonaryvein --> left atrium --> left ventricle --> aorta

Select one:

True

False

8. Capillaries are as wide as one red blood cell.

Select one:

True

False

9. The purpose of the coronary arteries is to bring oxygenatedblood to the walls of the heart so that the muscles in the heartwalls can contract.

Select one:

True

False

10. Vasodilation refers to the narrowing of blood vessels.

Select one:

True

False

ultramarinealligator67

True of False: Freshwater environments have a higher concentration of oxygen than saltwater environments.

QUESTION 2 If the difference in partial pressure of gas on either side of the barrier to diffusion is 0, which of these events will occur?

The area for gas exchange will increase to accommodate this similarity.

The constant for diffusion will decrease.

The rate of diffusion will be 0.

The distance thickness of the barrier to diffusion will also be 0.

QUESTION 3 On the x-axis of the oxygenâhemoglobin equilibrium curve is the partial pressure of oxygen in tissues. Which type of blood is most likely to be represented by the right-hand side of the axis? (Hint: the oxygen-hemoglobin equilibrium curve is figure 45.14 in your book on pg 913)

blood found in the left ventricle

blood found in the right atrium

blood found in the superior vena cava

blood found in the inferior vena cava

QUESTION 4 Which of these is an example of pulmonary circulation?

Blood is pumped from the right ventricle to the lungs.

Blood is pumped from the left ventricle to the aorta.

Blood is pumped from the aorta to the cardiac vein.

Blood is pumped from the inferior vena cava to the right atrium.

QUESTION 5 O2 will diffuse from blood to tissue faster in response to which of the following conditions?

an increase in the PO2 of the tissue

a decrease in the PO2 of the tissue

an increase in the thickness of the capillary wall

a decrease in the surface area of the capillary

QUESTION 6 Which of the following promotes oxygen release from hemoglobin?

a decrease in temperature

a decrease in carbon dioxide levels

a decrease in pH

a decrease in carbonic anhydrase

QUESTION 7 How does the medulla oblongata sense the amount of carbon dioxide in the blood?

A. Carbonic anhydrase produced by cells performing cellular respiration is exported and travels though the blood, and binds to a receptor on the medullary respiratory center, which causes a signal amplification resulting in a change in gene expression which results in the production of proteins that will cause the diaphragm to contract

B. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which increases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

C. CO2 produced by cells performing cellular respiration reacts with blood plasma for form an acid, which decreases the pH of the blood, which causes the medullary respiratory center to contract the diaphragm

D. A and B

E. A and C

QUESTION 8 Which of the following parts of the lung are considered "dead space"? A. The alveoli B. The trachea C. The bronchi D. B and C E. All of the above

QUESTION 9 Which of the following blood vessels have the thinnest walls?

arteries

arterioles

capillaries

venules

veins

QUESTION 10 How does the interstitial fluid return to the bloodstream?

A. Interstitial fluid flows into the capillary where the osmotic pressure driving fluid into the bloodstream is greater than the blood pressure driving fluid out of the blood

B. Interstitial fluid flows into the capillary where the blood pressure driving fluid into the bloodstream is greater than the osmotic pressure driving fluid out of the blood

C. Interstitial fluid leaves the tissue via lymphatic ducts and travels through the lymphatic system, which returns the fluid to the veins. D. A and C

E. B and C

QUESTION 11 True or False: When an electrocardiogram (EKG or ECG) shows a flat line (aka asystole), medical personnel will restart the heart using a defibrillator.

azureprairie-dog128

QuestionGroup: #37 CNS

Assigned as

Homework

Which parts of the brain contribute to our social behavior?

Orbitofrontal cortex

Mirror neurons

Amygdala

All of these are correct

Answered

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QuestionGroup: #38 CNS2

Assigned as

Homework

Part of the explanation of long term memory is which of the following?

Long term potentiation between neurons and muscle cells

Long term potentiation between neurons

Short term translation

Long term transcription

Answered

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QuestionGroup: #39 PNS

Assigned as

Homework

The somatic component of the peripheral nervous system has which of the following characteristics?

It controls the smooth muscle in the blood vessels so that blood vessels can vasoconstrict or vasodilate

It controls the autonomic nervous system so it indirectly controls heart rate

It controls your skeletal muscle so you can answer this question by pushing on the keyboard

It controls the smooth muscle in your intestinal tract so it controls peristalsis

Answered

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QuestionGroup: #40 Smooth/skeletal

Assigned as

Homework

Which of the following is NOT a part of a skeletal muscle cell?

Motor neurons

Nuclei

Sarcomeres

Actin

Myosin

Answered

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QuestionGroup: #41 Cardio

Assigned as

Homework

Which part of the circulatory system has the highest pressure?

Veins

Capillaries

Arteries

Aorta

Answered

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QuestionGroup: #42 Cardio2

Assigned as

Homework

Where do the electrical signals originate in your heart?

SA node

Internodal tracts

His-Purkinje System

AV node

Answered

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QuestionGroup: #43 Blood pressure

Assigned as

Homework

There was a horrific traffic accident and you run to help the victims. You feel a pulse from his carotid artery ,however the medic comes along and gets no blood pressure as he measures it from the arm. He claims the victim is dead. You think which of the following?

Medic is not correct since it is the difference between heart rate and blood pressure that determines life. No heart rate only means tha the sympathetics have stopped vasoconstricting the blood vessels.

Medic is correct since it is common to not have a blood pressure of 120/80 and no pulse due to stress as was discussed in class.

Medic is incorrect since there is a pulse. This means the person is still alive.

Medic is correct since there is no blood pressure there is no life.

Answered

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QuestionGroup: #44 Blood pressure2

Assigned as

Homework

Which side of the capillary bed has the higher oncotic pressure?

venous and lymph

arterial and lymph

lymph

venule side

arterial side

Answered

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QuestionGroup: #45 Capillaries

Assigned as

Homework

If the hydrostatic pressure is higher in the interstitial space rather than the capillary, which of the following will occur?

(2),(3)

(1),(2),(3)

(3) Decreased hydrostatic pressure in the arterial end of the capillary

(2) Decreased hydrostatic pressure in the venous end of the capillary

(1) No change in the hydrostatic pressure since this pressure is maintained regardless of external pressures.

Answered

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QuestionGroup: #46 Respiration/ ventilation

Assigned as

Homework

The left atrium is damaged and is generating a great resistance to blood coming from pulmonary vein. What happens due to this pressure?

Back up of blood in the pulmonary artery which causes pulmonary capillary edema

Generation of back flow into the inferior vena cava

Generation of coronary artery edema

Back up of blood in the pulmonary vein which causes pulmonary capillary edema

Answered

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QuestionGroup: #47 Respiration/ventilation 2

Assigned as

Homework

Edema in the pulmonary circulation refers to which of the following?

additional fluid in the trachea

additional interstitial fluid

additional surfactant

additional capillary fluid

additional intracellular fluid

Answered

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QuestionGroup: #48 Cell communication

Assigned as

Homework

What is the definition of a signaling pathway?

All the proteins in the nucleus

All the cell molecules in the mitochondria

A group of genes that control mitosis

A specific chemical pathway that is activated by the ligand/receptor complex.

Answered

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QuestionGroup: #49 Hormone/ menstruation

Assigned as

Homework

Which hormone directly causes ovulation?

Follicle stimulating hormone

Lutenizing hormone

Progesterone

Estrogen

All of these

BIOL125 Lecture Notes - Lecture 8: Sine Wave, Tunica Media, Varicose Veins

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