lecture 15 - cardiovascular - bio 105.pptx [read-only] 15...chapter 12 copyright © 2009 pearson...

11/20/2013

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Cardiovascular System

Biology 105

Lecture 15

Chapter 12

Copyright © 2009 Pearson Education, Inc.

Outline

I. Functions of cardiovascular system

II. Components of the cardiovascular system:I. Blood vessels

II. Heart

III. Regulation of the heartbeat

IV. ECG/EKG

V. Blood pressure

VI. Cardiovascular circuits

VII.Cardiovascular diseases

VIII.Lymphatic system

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Function of the cardiovascular system is to transport blood containing:

Nutrients

Waste

Hormones

Immune cells

Oxygen



Cardiovascular system consists of three components:

1. Blood

2. Blood vessels, through which blood flows

3. Heart, which pumps blood


Blood Vessels

Arteries

Arterioles

Capillaries

Venules

Veins

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Blood Vessels – Arterioles and Venules

Arteries divide into smaller vessels called arterioles, bringing O2, water, and nutrients to the tissues.

Arterioles divide into smaller vessels called capillaries.

Blood leaves the capillaries and enters venules.

Venules take CO2, water, and wastes away from the tissues.

Venules join together to form veins.


Blood Vessels

Blood vessels are lined with epithelial cells.

They have a layer of smooth muscles that constrict or dilate the vessels.

Blood vessels are covered with a layer of connective tissue.

The space inside the vessel is called the lumen.

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Vasoconstriction and Vasodilation

Vasoconstriction When muscle contracts and the diameter of the

lumen narrows, reducing blood flow.

Vasodilation When muscle relaxes and the diameter of the

lumen increases, increasing blood flow.


Blood Vessels

Figure 12.2

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Blood Vessels – Arteries and Veins

Arteries – always carry blood away from the heart and usually carry O2-rich blood. Aorta — largest artery.

Arterioles — smallest arteries (whether they are constricted or dilated affects blood pressure).

Veins – always return blood to the heart and usually carry O2-poor blood. Vena cava — largest veins in the body.

Venules — smallest veins.


The Cardiovascular System – Arteries

Figure 12.1 (2 of 2)

Arteries• Carry blood away fromheart

Carotid arteries• Deliver blood to the headand the brain

Aorta• Delivers blood to thebody tissues

Pulmonary arteries• Deliver oxygen-poorblood to the lungs

Coronary arteries• Deliver blood to theheart muscle cells

Renal artery• Delivers blood to thekidney

Iliac artery• Delivers blood topelvic organs andabdominal wall

Radial artery• Delivers blood tothe hand

Femoral artery• Delivers blood tothigh and inner knee


The Cardiovascular System – Veins

Figure 12.1 (1 of 2)

Veins• Carry blood back to theheart Jugular veins

• Carry blood from headto the heart

Renal vein• Carries blood from thekidney to the heart

Pulmonary veins• Carry oxygenated bloodfrom the lungs to theheart

Inferior vena cava• Carries blood from thelower body back to theheart

Superior vena cava• Carries blood from theupper body back to theheart

Iliac vein• Carries blood from thepelvic organs andabdominal wallback to the heart

Radial vein• Carries blood from thehand back to the heart

Femoral vein• Carries blood from thethigh and inner kneeback to the heart

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Blood Vessels – Arterioles

There are sphincter muscles that:

Contract to reduce blood flow to the capillaries.

Dilate to increase blood flow to the capillaries.


Blood Vessels

Figure 12.4b


Capillaries

Smallest vessels are called capillaries.

This is where components (O2, CO2, nutrients, waste) can pass from the blood vessels to other tissues, and from the tissues back into the blood vessels. Blood flow in capillaries is slow – this allows time

for the exchange of substances.

Capillaries do not have a smooth muscle layer.

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Capillaries

The RBCs stay in the blood vessels, but the oxygen leaves the RBCs and the capillaries and goes into the tissues.

The oxygen leaves the capillaries because there is a gradient – there is more oxygen in the capillaries than in the tissues.


Capillaries

Figure 12.3c


Capillaries

Figure 12.3a

Capillary cell

To tissue cells

Slit between cells

Nucleus

Red blood cell

(a) Substances are exchanged between the blood and tissuefluid across the plasma membrane of the capillary or throughslits between capillary cells.

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Pressures and their Effect on Capillaries

At the arterial end of the capillaries blood pressure forces fluid out of the capillary and into the tissue.

At the venous end, osmotic pressure draws fluid back into the vessel from the tissue.

Diffusion is the pressure that draws gases across the capillary.


Capillaries

Figure 12.3b


Can gas freely pass through the plasma membrane?

Tru

e

Fal

se

50%50%1. True

2. False

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Do RBCs leave the capillaries?

Yes N

o

50%50%1. Yes

2. No


Which kind of blood vessels bring blood back to the heart?

Arteries Veins

50%50%1. Arteries

2. Veins


Which kind of blood vessels have the presence of sphincters?

Capillaries Venules Arterioles Arteries

25% 25%25%25%1. Capillaries

2. Venules

3. Arterioles

4. Arteries

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This kind of pressure draws gases across the capillaries:

Osmotic Blood Diffusion

33% 33%33%1. Osmotic pressure

2. Blood pressure

3. Diffusion


This pressure draws fluid back into the capillaries:

Blo

od Pre

ssur

e

Osm

otic P

ress

ure

Diff

usion

33% 33%33%1. Blood Pressure

2. Osmotic Pressure

3. Diffusion


The Heart

Figure 12.7a

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Heart and Lungs

Figure 12.7b


The Heart

The heart is composed of four chambers and lies almost in the center of the thoracic cavity.

Two atria — thin-walled upper chambers that serve as reservoirs for blood. Two ventricles — thick-walled lower chambers

powering the pulmonary and systemic circuits.

Septum: separates right and left sides of the heart.


The Heart

Figure 12.7d

Superior venacava Aorta

Rightpulmonary

arteries

Pulmonarysemilunar valve

Right atrium

Rightpulmonary

veins

Rightatrioventricular

valve(tricuspid valve)

Chordae tendineae

Rightventricle

Inferior vena cava

Left pulmonaryarteries

Pulmonary trunk

Left pulmonary veins

Left atrium

Aortic semilunar valve(hidden from view)

Leftatrioventricularvalve (mitral valve)

Left ventricle

Myocardium

Endocardium

Pericardium

Septum(d)

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The Heart

There are valves which keep blood flowing forward:

Two atrioventrical valves (AV) — between atria & ventricles, making a “LUB” sound when closing.

Two semilunar vales (SL) — base of major arteries making a “DUB” sound when closing.


The Heart Valves

Figure 12.8


The Heart

Pericardium — thick membranous sac surrounding the heart (secretes serous fluid).

Myocardium — consists of cardiac muscle tissue, which contracts to pump blood.

The interior of the heart is lined by endocardium.

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Copyright © 2009 Pearson Education, Inc. Figure 12.7c

Oxygen-richblood

(to body)

Oxygen-poorblood(to lungs)

Oxygen-richblood(from lungs)

Oxygen-poorblood

(from body cells)(c)

Pathway of Blood Flow through the Heart


Pathway of Blood Flow through the Heart

Superior and inferior vena cava (O2-poor) right atrium

Right atrium tricuspid AV valve right ventricle

Right ventricle pulmonary SL valve pulmonary arteries lungs

Pulmonary veins (O2-rich) left atrium

Left atrium mitral AV valve left ventricle

Left ventricle aortic SL valve aorta rest of the body tissues…


Cardiac Cycle

Cardiac cycle – one complete heartbeat where both atria contract simultaneously (at the same time) followed by both ventricles contracting simultaneously.

Systole – when ventricles contract and pump blood out of the heart.

Diastole – when ventricles relax and receive blood from atria.

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Intrinsic control:

Sinoatrial node (SA) (pacemaker) –initiates the heartbeat and causes the atria to contract.

Atrioventricular node (AV) – causes the ventricles to contract.

Heartbeat Regulation – Intrinsic


The AV node relays the message to the ventricles using bundles of specialized muscle cells = atrioventricular bundle.

The bundle divides into smaller bundles of specialized cardiac muscle cells called Purkinje fibers.

Heartbeat Regulation – Intrinsic


Regulation of the Heartbeat

Figure 12.12 (1 of 5)

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Figure 12.12 (2 of 5)



Figure 12.12 (3 of 5)



Figure 12.12 (4 of 5)

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Figure 12.12 (5 of 5)


Extrinsic control of heartbeat – the autonomic nervous system and hormones can modify the rate of the heartbeat.

Heartbeat Regulation – Extrinsic


Electrocardiogram (ECG/EKG) – a recording of the electrical changes that occur in the myocardium during a cardiac cycle.

Recording the Heartbeat

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ECG/EKG

A typical ECG/EKG consists of three distinguishable waves:

P wave – atrial contraction

QRS wave – ventricle contraction

T wave – ventricle repolarization


ECG/EKG

Figure 12.13b


Pulse

As the heart pumps blood into the arteries, they expand such that one is able to feel a pulse.

The pulse rate is the same as the heart rate.

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Blood Pressure

Blood pressure Systolic – when the ventricles contract, sending

blood into the arteries

Diastolic – when the heart relaxes between beats


Blood Pressure

Sphygmomanometer:

Measures blood pressure.

Can provide early identification of hypertension, or high blood pressure. This is known

as the silent killer.


Blood Pressure

Figure 12.14 (1 of 2)

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Blood Flow

Blood flow in the arteries is due to the blood pressure from the heart’s pumping action.

The blood pressure in veins is very low.


Blood flow in veins is dependent upon:

1. Skeletal muscle contraction

2. One-way valves

3. Respiratory movements

Veins


One-Way Valves in Veins

Figure 12.6a

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One-Way Valves in Veins

Figure 12.6b

Valveclosed

Valveopen

Relaxed calfmuscles

Skeletal musclesrelax, and bloodfills the valvesand closes them.

Muscle contractionsqueezes the vein,pushing bloodthrough the openvalve toward theheart.

Valveclosed

Contracted calfmuscles

(b)


When ventricles relax and receive blood from atria this is called:

Sys

tole

Dia

stol

e

50%50%1. Systole

2. Diastole


Which blood pressure would be the highest?

1 2

50%50%1. Systolic

2. Diastolic

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Blood flow in veins is dependent upon one-way valves, respiratory movements, and:

Sm

ooth m

uscl

e

Ske

leta

l mus

cle

50%50%1. Smooth muscle

2. Skeletal muscle


Atrial contraction occurs during which ECGwave?

P wave QRS wave T wave

33% 33%33%1. P wave

2. QRS wave

3. T wave


The pacemaker which initiates the heartbeat is the:

AV node Purkinje fibers SA node

33% 33%33%1. AV node

2. Purkinje fibers

3. SA node

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The muscular layer of the heart wall is the:

Endocardium Myocardium Pericardium

33% 33%33%1. Endocardium

2. Myocardium

3. Pericardium


Cardiovascular System Circuits

Pulmonary circuit – flow of blood from the heart to the lungs and back to the heart, powered by the right ventricle.

Systemic circuit – flow of blood through the rest of the body, powered by the left ventricle.


Systemic Circuits

Renal circuit – supplies blood to the kidneys.

Hepatic portal circuit – supplies blood to the digestive organs, especially the liver.

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Systemic – Coronary Circuit

Supplies blood to the heart muscle itself.

Coronary arteries branch off the aorta.

Coronary arteries can become clogged and bypass surgery may be necessary.

Coronary veins return blood to the heart.


Coronary Circuit

Figure 12.10a

Inferiorvenacava

Superiorvena cava

Pulmonarytrunk

Aorta

Rightcoronary

vein

Rightcoronary

artery

Left coronaryartery

Leftcoronaryvein

(a)

Pulmonaryveins


Coronary Circuit

Figure 12.10b

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Disorders of the Cardiovascular System

1. High blood pressure

2. Atherosclerosis and coronary artery disease

3. Heart attack

4. Stroke

5. Aneurysm


Disorders – High Blood Pressure

High blood pressure is also called hypertension.

Causes: 90% of high blood pressure has no known cause.

Can be caused by kidneys not being able to balance sodium concentrations correctly.

Increased fluid in blood increases blood pressure.

Stress can lead to high blood pressure.


Disorders – High Blood Pressure

Result: causes the heart to work too hard. Leads to heart failure, kidney problems, blood

vessel problems, and death.

Prevention includes: lower salt intake, weight loss, exercise, and stop smoking.

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Disorders – Atherosclerosis

Atherosclerosis is a narrowing of the arteries due to fatty deposits and thickening of the arterial wall.

Can lead to heart attack or stroke.

When this occurs in the arteries of the heart muscle, it is called coronary artery disease.


Coronary Artery Blockage

Some LDL can become damaged through oxidative stress. Damaged LDL can get stuck in coronary arteries.

The immune system reacts to this by mounting an inflammatory response = blood clot.

The oxidized material can build-up and reduce the flow of blood to the heart = coronary artery blockage.


Atherosclerosis

Figure 12.16a

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Atherosclerosis

Figure 12.16b


Atherosclerosis

Figure 12.16c


Disorders – Heart Attack/Myocardial Infarction

Heart muscle dies because of an insufficient blood supply during a heart attack (myocardial infarction) and is gradually replaced by scar tissue.

Can be caused by coronary artery blockage.

Scar tissue cannot contract, so part of the heart permanently loses its pumping ability.

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Disorders – Stroke

Cranial arteriole bursts or becomes blocked, reducing blood supply to an area of the brain.

The result is that a portion of the brain dies, and may result in paralysis or death.


Disorders – Aneurysm

A weak spot in a blood vessel causes the vessel to balloon out and possibly rupture.

In the brain: may cause a stroke.

In the aorta: may cause death.


Lymphatic System

This system returns excess tissue fluid to the blood stream (subclavian veins).

Skeletal muscles and valves keep fluid moving.

Also responsible for:1. Transportation of products of fat digestion.

2. Defense against disease-causing organisms and abnormal cells.

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Lymphatic System

Figure 12.21 (1 of 2)

Anchoringfilaments

Interstitialfluid

enters

Endothelium

Flaplikeminivalve

Tissue cells


Components of the Lymphatic System

Lymph

Lymphatic vessels

Lymphoid organs


Lymphatic System

Figure 12.22a

Tonsils• Protect the throatagainst bacteria andforeign agents

Right lymphatic duct• Returns the lymph fromthe upper part of bodyto the blood Thymus

• Site where Tlymphocytes mature,enabling them to fightspecific disease-causingorganisms Thoracic duct

• Returns lymph frommost of the body tothe blood Spleen

• Site of lymphocyteproduction• Removes old redblood cells, foreigndebris, andmicroorganisms fromthe blood

Lymph vessels• Return excess interstitialfluid to the blood• Some transport products offat digestion to the blood

Lymph nodes• Filter lymph beforereturning it to the blood• Contain lymphocytesand macrophages thatdefend againstdisease-causingorganisms

(a) The lymphatic system returns the fluid tothe bloodstream that previously left thecapillaries to bathe the cells, protectsagainst disease-causing organisms, andtransports products of fat digestion fromthe small intestine to the bloodstream.

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Lymphoid Organs

1. Lymph node: cleanses lymph of debris/pathogens, and stores lymphocytes/ macrophages to fight infection.

2. Spleen: cleanses the blood, and removes old blood cells.

3. Red bone marrow: produces both B and T cells.

4. Thymus gland: where T cells mature.

5. Tonsils: recognize infectious agents entering the body.


Lymph Node

Figure 12.22b


The blood supply to the kidneys is the:

Hep

atic

porta

l circ

uit

Ren

al c

ircuit

Car

diac

circ

uit

33% 33%33%1. Hepatic portal circuit

2. Renal circuit

3. Cardiac circuit

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This lymphoid organ produces B and T cells:

Spleen Thymus Lymph node Red bone

marrow

25% 25%25%25%1. Spleen

2. Thymus

3. Lymph node

4. Red bone marrow


These vessels always carry blood away from the heart:

Arte

ries

Vei

ns

50%50%1. Arteries

2. Veins


What are the small blood vessels where the oxygen and carbon dioxide transfer between the blood and tissues?

Arte

riole

s

Ven

ules

Cap

illar

ies

Lac

teal

s

25% 25%25%25%1. Arterioles

2. Venules3. Capillaries

4. Lacteals

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Important Concepts

Read Chapter 12

What are the functions and components of the cardiovascular system?

What are the components of the blood vessels and their functions? What would the cross-section of a vein, artery,

and capillary look like?


Important Concepts

What is the path of the blood through the body (starting with the aorta, which kinds of blood vessels does the blood pass through before returning to the heart)?

How do arterioles affect blood pressure?

What are the pressures that cause fluid to enter and leave the capillaries, and what pressure causes gases to enter and leave the capillaries?


Important Concepts

What is the function of capillaries?

What are the chambers of the heart?

What is the pathway of blood flow through the heart?

You should be able to describe the cardiac cycle!

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Important Concepts

What are heart valves? Where are they located, when are they opened, and when are they closed?

How is the heartbeat regulated, both intrinsically and extrinsically?

What records the electrical changes that occur in the myocardium during a cardiac cycle?


Important Concepts

What are the three waves on the ECG, and what happens during each of the waves on the ECG?

What measures blood pressure?

What causes blood to flow in the arteries and in the veins?

What are the pulmonary, systemic, renal, hepatic portal, and coronary circuits? (Which tissues do they go to?)


Important Concepts

What are the causes and effects of the cardiovascular diseases discussed in lecture?

How can you prevent high blood pressure?

What are the functions of the lymphatic system? What are the components of the lymphatic

system and their functions?

What causes fluids to travel through lymphatic vessels?

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Definitions

Lumen, vasoconstriction, vasodilation, osmotic pressure, blood pressure, septum, capillary, artery, vein, arteriole, venule, vena cava, aorta, sinoatrial node (SA), atrioventricularnode (AV), pericardium, myocardium, endocardium, cardiac cycle, systole, diastole, atrioventricular bundle, Purkinje fibers, extrinsic control, intrinsic control, electrocardiogram, pulse, systolic pressure, diastolic pressure, sphygmomanometer, coronary arteries, renal circuit, hepatic portal circuit, coronary circuit, hypertension

lecture 15 - cardiovascular - bio 105.pptx [read-only] 15...chapter 12 copyright © 2009 pearson...

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