nigga

Arteries

Carry blood away from the heart.

Arteries

Thick-walled composed of distinct layers.

Arteries

Outer and inner layers primarily made of connective tissue.

Arteries

Middle layers made up of smooth muscle and elastic fibers.

Arteries

Expand and contract to accommodate the inrush of blood.

Pulse

Change in the diameter of arteries following heart contractions.

Pulse

Can be felt near your wrist (radial artery) and on neck (carotid artery).

Arterioles

Smaller branches of arteries leading to capillaries.

Autonomic nervous system

The part of the nervous system that controls the motor nerves that regulate equilibrium, and that is involuntary.

Vasoconstriction

Narrowing of blood vessels, allowing less blood to the tissues.

Vasoconstriction Example

Becoming pale when frightened - constriction of the arteriolar muscles diverts blood away from the outer capillaries of the skin toward the muscles.

Vasodilation

Widening of blood vessels, allowing more blood to the tissues.

Vasodilation Example

Blushing - vasodilation of arterioles leading to skin capillaries and red blood cells close to the surface of the skin produce a pink color.

Atherosclerosis

A degeneration of blood vessels caused by the buildup of fatty deposits (plaques) in the inner wall.

Arteriosclerosis

Hardening and thickening of the artery walls that cause the blood to flow less efficiently.

Arteriosclerosis Effects

Can increase blood pressure.

Arteriosclerosis Effects

Can cause heart attack or stroke.

Blood Clots

May form in narrowed arteries.

Aneurysm

A bulging or weakened section of an artery wall.

Aneurysm Common Sites

Most common sites: aorta, brain, legs, spleen.

Aneurysm Causes

Most commonly caused by high blood pressure or genetic disorders.

Stroke Sign - Weakness

Sudden loss of strength or sudden numbness in the face, arm, or leg, even if temporary.

Stroke Sign - Trouble speaking

Sudden difficulty speaking or understanding or sudden confusion, even if temporary.

Stroke Sign - Vision problems

Sudden trouble with vision, even if temporary.

Stroke Sign - Headache

Sudden severe and unusual headache.

Stroke Sign - Dizziness

Sudden loss of balance, especially with any of the above signs.

Capillaries

Extremely narrow (red blood cells must travel through capillaries in single file)

Capillaries

Only one cell layer thick

Capillaries

Site of gas, nutrient, and waste exchange between blood and body cells

Capillary beds

Networks of capillaries that supply blood to tissues

Oxygenated blood

Appears bright red

Deoxygenated blood

Appears dark red or bluish

Deoxygenated blood

Collects in small veins called venules and is carried back to the heart

Veins and Venules

Walls contain thin layers of smooth muscle

Veins and Venules

Venules merge into larger veins leading to the heart

Blood flow

Slows down as it moves from arteries to arterioles to capillaries, and blood pressure in these smaller vessels decreases

Veins

Have one-way valves, steering blood back to the heart

Skeletal muscles

Aid in blood flow in veins by contracting and squeezing the veins, directing blood flow toward the heart

Pericardium

Sac around the heart (protection)

Myocardium

Middle layer, cardiac muscle

Endocardium

Inside layer, protective

Heartbeat Sounds

Electrical conduction of the heart = heartbeat!

LUB

Slamming of atrioventricular (tricuspid & bicuspid) valves

DUB

Slamming of semilunar (pulmonary & aortic) valves

Heart beats intrinsically

Self-regulated - not stimulated by external nerves - will continue to beat outside of the body for a short period on its own

Heart murmur

Abnormal heart sounds, often caused by leaky or malfunctioning valves

Heart rhythm

Set by the SA node (sinoatrial node) in the upper right atrium - also called the 'pacemaker'

Vagus nerve

Stimulates the SA node. Sympathetic nervous system stimulation will speed it up and parasympathetic nervous stimulation will slow it down.

AV node

Causes delayed contraction of the atria.

Bundle of His

Passes the electrical impulse along to the Purkinje fibers.

Purkinje fibers

Super conduct the impulse through the ventricles to cause ventricular contraction.

Tachycardia

SA signals speed up, resulting in a fast heart rate.

Bradycardia

SA signals slow down, resulting in a slow heart rate.

Pacemaker

Device implanted to help set the heart rate.

Hydrostatic pressure

Any fluid confined in a vessel exerts a push against the walls that contain it.

Blood pressure increase factors

If the blood vessel narrows, pressure increases; if blood volume increases, pressure increases.

Blood pressure decrease factors

If the blood vessel expands in diameter, pressure decreases; if blood volume decreases, pressure decreases.

Normal BP

Ranges from 110/70 to 120/80 mmHg.

Systolic Pressure

Pressure when the heart contracts.

Diastolic Pressure

Pressure when the heart relaxes.

Hypertension risk factors

Smoking, obesity, high salt diet, lack of exercise, genetics.

Cardiac Output

Increase in cardiac output causes an increase in blood pressure.

Peripheral Resistance

A decrease in diameter (vasoconstriction) increases blood pressure, while an increase in diameter (vasodilation) decreases blood pressure.

Baroreceptors

Detect increased pressure in carotid arteries when blood pressure is too high.

Medulla oblongata

Sends signals to slow down the heart when blood pressure is too high.

Arterioles vasodilate

Reduces blood pressure when it is too high.

Sympathetic nerves

Stimulate the heart to beat faster and arterioles to constrict when blood pressure is too low.

Negative Feedback Loop

Mechanism that regulates blood pressure by adjusting heart rate and vessel diameter.