Pulmonary: Blood enters right atrium from vena cava > tricuspid valve > right ventricle > pulmonary artery > lungs > pulmonary vein

Systemic: Pulmonary vein > Left atrium > Mytrial Valve > Left ventricle > Aortic valve > Aorta > Arteries > Capillarys > Veins

Pulmonary: Low pressure (12 mm Hg) - Good for gas exchange

Systemic: High Pressure (90-100 mm Hg) - Good for transporting and traveling distances against gravity

1. Semilunar (Aortic and Pulmonary)

2. AV Valves (Tricuspid and Mytrial)

Aorta/Systemic - 100-120 mm Hg

Capillaries - 30 mm Hg

Veins - 12 mm Hg

Vena Cava - 0 mm Hg

Volume

64% Veins

16% Arteries

4% Capillaries

4% Left ventricle

4% Right ventricle

Pressure

Greatest at Aorta (90-100 mm Hg)

No pressure in vena cava (0 mm Hg)

1. Intima - Elastic layor - able to bend and move flexibly

2. Media - Consists mostly of smooth muscle that constricts or dilates the vessels based on the ANS and the release of Alpha receptors

3. Externa - Fibrous and connective tissue - Tough to protect the arteries

The diameter of an atriole is determined by the degree of contraction of the smooth muscle, which is mediated by the ANS (alpha-1 receptors)

* The diameter of the artery/arteriole is determined by the degree of contraction of the smooth muscle, which is mediated by the SNS (alpha receptors).

Constrict blood vessels

Increase Blood Pressure

Increase Heart Rate

Increase Conductability

Release Renin

SNS - Sympathetic fibers innervate (send signals) to arteries, causing them to constrict or relax, to maintain blood pressure.

Alpha 1 receptors are in charge of constricting or relaxing the arteries.

1. Carry blood back to the heart

2. Store blood

What is the pressure of the venules?

The Vena Cava?

Venules: 10 mm Hg

Vena Cava: 0 mm Hg

In veins and arteries, the endothelial cell layer is compact; the cells are close together so blood does not escape the systemic circulation in unwanted places.

In capillaries, the endothelial cells are loosely connected, allow nutrients, particles, gas and other particles into the blood stream. The capillaries do not allow large protein molecules in.

1. Endotelium cells

2. Basement membrane

Norepinephrine is released from the ANS, which activate the Alpha-1 Receptors. Alpha-1 Receptors cause calcium channels to open, which produces vasoconstriction

Calcium Causes Contraction

Neural Mechanism (Regulate CO and BP to control how much of blood is sent to the tissues or organs)

Local Control Mechanisms (Local vasoconstriction or dilation mediated by the CNS OR by organ intrinsic mechanisms)

Histamine: Dilates blood vessels - Increase blood flow to local vessels

Seratonin: Constricts blood vessels - Decrease blood flow to local vessels

Vasodilation: Nitric Oxide

Vasoconstriction: Prostaglandins, Angiotensin II and Endothelins

Endocardium - inner layer

Myocardium - Thick muscle surrounding the heart

Viscerial Pericardium - Outside of the heart - Start of the pericardium cavity

Parietal pericardium - Outermost layer - surrounds the pericardial cavity

Leukemia and cancers of the blood

Cancers of the blood do not produce tumors - instead they inflame organs by filling pleural spaces around the lungs

Electrical impulses that set the pace of the heart

Stimulates the myocardium (heart muscle) to contract and pump blood

Atrial Conduction

Ventricular Conduction

SA Node

60-100 BPM

Beta 1 receptors from the SNS stimulate an increased heart rate

Muscarinic receptors decrease heart rate

AV Node

40-60 bpm

Function: Ventricular Contraction

BPM: 15-40 BPM

ECG:

What does the P stand for?

ECG:

What does the QRS Stand for?

ECG:

What does the T stand for?

ECG:

When does the atrial repolarize?

Systole: Contacting

Diastole: Relaxing

1. Isovolumetric Contraction

2. Ejection

Isovolumetric relaxation

Rapid Filling

Tachycardia

Heart

1. Body Activities

2. Stroke Volume

3. Heart Rate

Direct

Heart rate increases : Cardiac Output increases

Activation of Beta-1 Receptors: HR Increases

Activation of Muscarinic Receptors: HR Decreases

Inverse

Heart Rate Increases : Diastolic Filling Decreases

1. Decrease

2. Decrease

1. Venous Return

2. Stretch of the muscle fibers

Alpha = After > Alpha receptors constrict vessels after the eart

Beta = Before > Beta receptors control heart rate before the blood goes out to the periphery

The normal heart will pump what is given. The more venous return, the more force the ventricle will develop, the more blood it will pump.

At High volumes, the heart muscles become over stretched and contractility decreases.

Arterial Pressure

(Right (Pulmonary) and Left (Systemic) Ventricle)

Stenosis/Narrowing of the artery (The heart has to develop increased pressure to open the diseased valve)

Diastolic Hypertension (Increases pressure to open aortic valve)

What is important in people with normal hearts?

A. Afterload

B. Preload

C. Contractility

1. Determined by Biochemical and Biophysical properties that govern actin and myosin interactions in myocardial cells.

2. Activation of Beta-1 Receptors in the ventricles by norepinephrine increases the availability of calcium ions and increases contractibility.

Long Term: 

* RAAS

* Kidneys control blood volume as well as RAAS (long term mechanism of BP control)

Short Term

* Autonomic Nervous System (ANS)

Sensory:  Baroreceptors in the aortic arch and carotid artery

 CNS: Autonomic centers in the brainstem

Motor:  Cardiac muscle, cardiac conduction system, and vascular smooth muscle.

1. Rapidly

2. Cannot

1. Reabsorbs water by the kidneys

2. Increased Extracellular Water Volume

*Note: Hypothalamus stimulates thrist so the person is ingesting more fluids.

1. Blood pulls in lower part of the body when the standing position is assumed >

2. Causing a decreased venous return, Decreased Cardiac Output and blood flow to the brain is inadequate®

 3. Causing dizziness, syncope (fainting), or both

1. Reduced blood volume, reduced preload (dehydration)

2. Drug-induced

3. Aging - sluggish reflexes, including baroreceptors

4. Bed Rest

5. Disorders of the ANS

1. Diuretics: Reduce preload by dehydrating the patient

2. Beta and Alpha-1 Blockers: Impair the baroreceptor reflex

3. Calcium Channel Blockers: Impairs venous return; reduced preload

1. Alleviate Cause (Rehydrate, Meds)

2. Help cope with the disorder, prevent falls and injuries,

1. Cardiovascular Disorders

Examples

1. Myocardial Infarction

2. Heart Failure

3. Stroke

4. Vascular Disease

Essential Hypertension

* Chronic rise in blood pressure that occurs with out evidence of other diseases.

(90-95%)

Elevation of Blood Pressure comes from some other disorder

(Ex: Kidney Disease, Chronic Renal Failure, Disorders of Adrenocorticoid hormones - pheochromocytoma)

Hypertension Definitions

JNC-VII

•Family history

•Age related changes

•Insulin resistance, metabolic syndrome, diabetes (especially type II)

•Race