ANAT 261 Lecture 11: Lecture 11 – Blood Vessels

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indigospider512

18 Feb 2019

School

McGill University

Department

Anatomy & Cell Biology

Course

ANAT 261

Professor

Craig A.Mandato

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October 10th, 2017

Lecture 11 - Blood Vessels

Circulatory System: Composed of the Heart and Vascular System

The Vascular System:

• Efferent Vessels: Arteries leaving the heart to transport

nutrients and oxygen to the tissues. Nutrients and

oxygen diffuse out of the blood vessels and into the

tissues at the level of the capillary network.

o Large arteries: aorta and carotid artery

• Afferent Vessels: Veins returning to the heart, carrying

CO2 and metabolic waste from the tissues

o Large Veins: Superior and Inferior Vena Cava

Cross-Section (aka Transverse Section) of Blood Vessels

• Veins and arteries run in parallel to each other (as seen on

image on the left)

• Consequence: Arteries and veins appear side by side and

running in the same direction when being viewed in cross-

section

o Advantage of looking at blood vessels in cross

section

• Examples:

o Large artery will appear next to a large vein

o Muscular artery will appear next to a muscular vein

o Arteriole will appear next to a venuole

o Metarteriole will appear next to a post-capillary

venuole

• When looking at a cross-section of blood vessels the

smooth muscle cells (of the media layer) will appear in

longitudinal section

• Comparing Arteries and Veins in Cross-Section

o Both veins and arteries may have red blood cells in the lumen (space in the

middle)

o When trying to differentiate between arteries and venules in cross-section, look

at the shape, thickness of the media and whether the structure is collapsed.

o Shape:

▪ Artery: shape will appear round (not collapsed)

• Artery keeps its shape because the Media layer (M) is very large,

you have many layers of smooth muscle cells

▪ Vein: Shape is Oval (tends to be collapsed) and may appear much larger

than this one (in the femur, muscular artery and vein example)

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October 10th, 2017

• Has a very thin Media Layer (M) which contains much fewer

smooth muscle cells than an artery of equal size and it and has an

adventitia (dense irregular CT) that is very large compared to the

Media Layer.

▪ Why the artery keeps its shape but the vein doesn’t:

• The wall of the vein (Media Layer) is very thin (compared to the

artery). Therefore, when you fix the tissue with formaldehyde you

will see that the arteries keep a nice shape due to its large Media

of smooth muscle cells (supporting it) and the Vein tends to be

collapsed due to its very thin Media.

Longitudinal Section of Blood Vessels

• Runs in same direction as blood vessel (blood vessels run longitudinally along the body)

• When looking at the Media Layer of Blood Vessels in longitudinal section, the smooth

muscle cells will appear in cross section

Perfect Longitudinal Section

• In a perfect longitudinal section (cut for example right down the middle of the artery

and the vein) you will still see the Artery right next to the Vein, except now you will see

them in a longitudinal orientation

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October 10th, 2017

• Note: Structures (blood vessels) don’t always appear straight, they may appear

curved/distorted like in the example below (due to plane of section)

• Muscular Artery (from longitudinal section shown below):

o Longitudinal section

o Lumen has some RBC inside

o Media Layer (M) is still very thick

• Muscular Vein

o Practically has no Media, you only Adventitia

o Adventitia of the vein is fused with the adventitia of the artery

o Lumen appears red in this slide because of red blood cells

• Comparing Arteries and Veins in longitudinal Section (same way as you would in cross

section):

Longitudinal Sections may have ONLY an artery or a vein

• You lose your point of reference, there’s no artery to compare it to so it’s harder to see

that it’s a vein

• You can still identify whether it’s an artery or a vein using the same rules for comparing

arteries to vein: Look at (1) shape, (2) Media Layer, and (3) whether or not it’s collapsed

o In longitudinal section, it’s hard to identify whether it’s collapsed so focus on

Media Layer

o Ex (Slide below): There is practically no visible media, all you really see are

Endothelial cells covering the surface of the vein

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Document Summary

Circulatory system: composed of the heart and vascular system. The vascular system: efferent vessels: arteries leaving the heart to transport nutrients and oxygen to the tissues. Nutrients and oxygen diffuse out of the blood vessels and into the tissues at the level of the capillary network: large arteries: aorta and carotid artery, afferent vessels: veins returning to the heart, carrying. Co2 and metabolic waste from the tissues: large veins: superior and inferior vena cava. Media layer: why the artery keeps its shape but the vein doesn"t, the wall of the vein (media layer) is very thin (compared to the artery). In a perfect longitudinal section (cut for example right down the middle of the artery and the vein) you will still see the artery right next to the vein, except now you will see them in a longitudinal orientation. In longitudinal section, it"s hard to identify whether it"s collapsed so focus on.

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

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

Change your responses to resubmit

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

Change your responses to resubmit

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

Change your responses to resubmit

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

Change your responses to resubmit

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

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.

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ANAT 261 Lecture 11: Lecture 11 – Blood Vessels

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