BCMB 230 UTK Exam 3

What Body Systems Affect the Cardiovascular System?

- Endocrine, nervous, and urinary systems

3 Main Components of Cardiovascular System

1: The Heart

2: Blood Vessels

3: Blood

Heart Component of Cardiovascular System

- The Pump Itself

Blood Vessels Component of Cardiovascular System

- Tubes carrying blood around the body

Blood Component of Cardiovascular System

- Liquid connective tissue containing many different nutrients and other products

The 3 Layers of the Heart

1. Epicardium

2. Myocardium

3. Endocardium

Epicardium

- Outer layer of the heart

- Made up of fibrous tissue

Myocardium

- Middle layer of the heart

- Muscular

Endocardium

- Inner layer of the heart

- Made of endothelial cells (continuous with the lining of blood vessels)

Blood Flow Through The Heart

Deoxygenated Blood

1-Superior & Inferior Vena Cava

2- Right Atrium

3-Tricuspid Valve

4- Rt Ventricle

5-Pulmonary Valve

6-Pulmonary Artery

7- Lungs pick up oxygen

Oxygenated Blood

8-Pulmonary Veins

9- Lt Atrium

10- Mitral Valve (Bicuspid)

11-Lt Ventricle

12- Aortic Valve

13- Aorta

14- Body tissues

Semilunar Valves

- Pulmonary valve and aortic valve

- Separate the ventricles from the great arteries

- Prevent back-flow of blood in heart

AV Valves

- Bicuspid (mitral) and Tricuspid valve

- Separate atria from ventricle

- Prevent back-flow of blood in heart

Atria

- At the top of the heart

Ventricles

- At the bottom of the heart

- Have thicker muscle walls so that they are stronger and can p

Chordae Tendineae

- "Strings" within the heart that hold the valves in place to prevent blood from flowing backward

- aka "heart strings"

Cardiac Output (CO)

- Volume of blood pumped out of the left ventricle in one minute.

Heart Rate (HR)

- Number of cardiac cycles (heartbeats) per minute

- Denoted in beats per minute (bpm)

Stroke Volume (SV)

- Amount of blood pumped out of the ventricles per heartbeat

- Denoted as (mL/beat)

Cardiac Output

- Heart Rate x Stroke Volume

- Overall performance of heart

Factors Affecting Heart Rate

- Autonomic innervation

- Hormones

- Fitness levels

- Age

Factors Affecting Stroke Volume

- Heart size

- Fitness levels

- Gender

- Contractility

- Duration of Contraction

- Preload (EDV)

- Afterload (resistance)

Blood Pressure

- Force that exerts on the blood vessel wall

- Difference in pressure in vessels allows for the flow of blood

2 Readings:

- Systolic (Top #): Systole represents ventricular contraction

- Diastolic (Bottom #): Represents ventricular filling

Blood Resistance

- Force that hinders blood flow

- Vessel diameter, length, and blood viscosity

Blood Flow

- Rate that blood moves through the vessel

- Blood Flow = Blood Pressure/Resistance

Cardiac Communication

- Contains excitable cells that make up the conducting system of the heart

- System initiates heartbeat and helps spread action potential throughout the heart

!! Communicate via gap junctions

2 nodes present:

1: SA node

2: AV node

SA node (sinoatrial node)

- The pacemaker of the heart

AV node (atrioventricular node)

- Receives signal from SA node to help ventricles contract

Conducting System of the Heart

- SA node -> AV node -> Bundle of His -> Left/Right Bundle Branches -> Purkinje fibers

First Step of Cardiac Excitation

1) The SA node sends signals to the AV node

Second Step of Cardiac Excitation

2) Atria becomes depolarized by the SA node and contracts

- AV node holds onto the signal for a moment to prevent atria and ventricles from contracting at the same time

Third Step of Cardiac Excitation

- AV node allows the signal to progress, and it is spread by the Purkinje fibers

Fourth Step of Cardiac Excitation

- Ventricles can now contract

Fifth Step of Cardiac Excitation

- Cyclical Process

Sequence of Cardiac Excitation and Reading an EKC

- P Wave

- QRS complex

- T wave

P Wave in an EKG

- Represents atrial depolarization

QRS Complex in an EKG

- Represents ventricle depolarization

T Wave in an EKG

- Represents ventricle repolarization

Arteries

- Carry O2- rich blood away from the heart

Veins

- Carry O2-poor blood toward the heart

Arterioles

- Small arteries

Venules

- Small veins

Capillaries

- Smallest of blood vessels

- Site of gas exchange

Veins vs. Arteries

Arteries:

- Contain thick muscular layers that contract to help move blood forward

- No valves

Veins:

- Do not have thick muscular layers

- Rely on surrounding muscles to contract and push blood

- Contain valves

!!! Both contain 3 layers

3 Layers of Veins and Arteries

1) Endothelium

2) Smooth Muscle

3) External Lamia

3 Types of Capillaries

1) Continuous

2) Fenestrated

3) Sinusoidal

Continuous capillaries

- Complete basement membrane

- Complete endothelial layer

- Found in the blood-brain barrier and skin

Fenestrated Capillaries

- Complete basement membrane

- Endothelial layer has holes in it to aid in diffusion

- Found in kidney, small intestine, spleen, and bone marrow

Sinusoidal Capillaries

- Incomplete basement membrane

- Large gap between cells

- In liver, spleen, bone marrow, and endocrine glands

Vasoconstriction

- Blood vessels shrink in diameter

- Raises blood pressure

Vasodilation

- Blood vessels increase in diameter

- Lowers blood pressure

Components of Blood

1) Formed Elements: 45% of blood

1a) Red Blood Cells (erythrocytes)

2b) White Blood Cells (Leukocytes)

3c) Platelets (Thrombocytes)

2) Plasma: 55% of blood

Blood Plasma

- Liquid portion of blood

- Carries blood cells, nutrients, proteins, metabolic wastes, and other molecules

Red blood Cells

- Small and flexible with no nucleus or organelles when mature

- Shaped like a biconcave disk (gives a high surface to volume ratio to aid in gas exchange)

- Function: Gas transport (both O2 and CO2)

- Contains hemoglobin- Protein that reversibly binds to O2 and CO2

Hemoglobin

- Spleen filters the blood and removes old RBCs, which are then sent to the liver to be broken down

- Iron is conserved and brought to the bone marrow by a protein called transferrin so it can be reused to make new RBCs

- Excess iron is stored in the spleen and liver by binding to a protein called ferritin

- Heme is converted into bilirubin

- Globulin proteins are broken down, and their AAs are reused

Jaundice

- Yellowing of skin caused by build-up of Bilirubin

Erythropoiesis

- Production of red blood cells in bone marrow

- Triggers differentiation of stem cells in bone marrow, signaling them to mature into RBCs

Erythropoetin

- Hormone made by the kidney which stimulates erythropoiesis

- Secreted in response to low O2 concentration in tissues (hypoxia)

White Blood Cells

- Made in bone marrow

- Function: All are immune cells that fight infection

2 Main Categories:

1) Granulocytes

2) Agranulocytes

Granulocytes

Neutrophils, eosinophils, basophils

- Contain granules in their cytoplasm

Agranulocytes

- Monocytes and lymphocytes

- Do NOT contain granules in their cytoplasm

Neutrophils

- Phagocytes whose release is stimulated during infection

- First to arrive at infection

- Found in blood and tissues

Eosinophils

- Fight infection by injecting their toxic granules into parasites

- Capable of phagocytosis

Basophils

- Secrete anti-clotting factor called heparin

- Also secrete histamine which attracts WBCs

Heparin

- Anticoagulant which makes you bleed longer to flush bacteria from wound

Monocytes

- Phagocytes that only circulate within the blood temporarily. - - Migrate into tissues and organs to later develop into macrophages to fight at the site of infection

Macrophages

- Large phagocytes capable of engulfing viruses and bacteria

Lymphocytes

- Two main types (T and B Lymphocytes that protect against specific viruses, bacteria, toxins, and cancer cells

Platelets

- Non-nucleated cell fragments containing numerous granules

- Causes blood clotting

Makeup of Blood Plasma

~ 91% water

- 7% proteins: Albumins, Globulins, Fibrinogen, other specialized enzymes and proteins

2% other solutes:

- Electrolytes: Na+ and K+

- Nutrients: AAs and lipids

- Gases: O2 and CO2

- Wastes: Bilirubin and Urea

- Vitamins

- Regulatory Substances

Albumins

- Aid in transport of other proteins

Globulins

- Antibodies

Fibrinogen

- Clotting factor

Hemostasis: Blood Coagulation

1) Vascular Spasm

2) Formation of Platelet Plug

3) Platelet Plug/Clot Formation

Vascular Spasm

- Cells contract and release chemicals to make muscles within the walls of the blood vessel contract in response to damage to endothelial cells

- Results in cell division and release of other proteins that attract other blood cells to the area.

- Release Von Willebrand Factor, which makes endothelial cells "sticky" so that recruited cells can begin to seal up damaged blood vessel

Formation of Platelet Plug

- Platelets begin to adhere to the Von Willebrand Factor.

- Begin to aggregate and form a Platelet plug, further sealing the area.

- Forms thrombus which mostly consists of a protein called fibrin

Protein that Forms Most of the Thrombus

- Fibrin

Platelet Plug/Clot Formation

- Blood coagulates, forming a scab and sealing the injured blood vessel.

- A protein called fibrin stabilizes the clot and keeps it in place

Blood pH

- 7.35-7.45

- Slightly Basic

- CO2 is the body's acid

- Bicarbonate is the body's base

2 Parts of the Circulatory System

1. Pulmonary circulation

2. Systemic circulation

Pulmonary Circulation

- Flow of deoxygenated blood from heart to lungs so it can be reoxygenated

Systemic Circulation

- Flow of oxygenated blood from the heart to the body and the return of deoxygenated blood from the body back to the heart

Arteries vs. Veins

Arteries: Carry blood AWAY from the heart

Veins: Carry blood to the heart

Pulmonary Artery

- Transfers O2-Poor blood away from heart to the lungs

Pulmonary Vein

- Carries O2-rich blood from lungs back to the heart so it can be circulated

Diffusion Gradients

- Drives the movement of gases, nutrients, and waste into and out of the bloodstream

- Osmotic gradients drive diffusion

Regulation of the Cardiovascular System

- Autoregulation

- Neural Mechanisms

- Endocrine Mechanisms

Autoregulation

- Local vasodilators (O2 and CO2) and constrictors (chemicals released by damaged tissues)

Neural Mechanisms

- Medulla can control heart rhythm, blood flow, and gas levels in the blood

Short Term Endocrine Mechanisms

- Epinephrine and norepinephrine

Long Term Endocrine Mechanisms

- Erythropoietin (hormone telling bone marrow to make RBCs)

Congestive Heart Failure

- Heart is unable to pump its required amount of blood

Arrythmia

- Abnormal heart rhythm

Myocardial Infarction (Heart Attack)

- Part of the heart dies because an artery becomes clogged and blocks the blood supply to the myocardium

Atherosclerosis

- The build-up of fats, cholesterol, and other substances in and on the artery walls.

Arteriosclerosis

- Hardening of arteries

- Makes arteries less effective at pumping blood

Arteriostenosis

- Narrowing of the lumen of an artery

Anemia

- Decrease in O2-carrying capacity of blood

- Reduced concentration of hemoglobin

Sickle Cell Anemia

- Genetic mutation resulting in one amino acid change and, therefore, changing the shape of hemoglobin into a sickle

- Painful and can also block blood vessels

Apnea

- Cessation of breathing

Dyspnea

- Labored breathing