circulatory and lympathic system bio 20

Arteries

Carry blood away from the heart.

Arteries Structure

Composed of distinct layers.

Arteries Layers

Outer and inner layers primarily made of elastic and fibrous tissue.

Middle Layers of Arteries

Made up of smooth muscle tissue.

Arteries Function

Expand to accommodate the inrush of blood.

Pulse

Change in the pressure of blood following heart contractions.

Pulse Location

Can be felt near your wrist and on the neck.

Arterioles

Small blood vessels that lead to capillaries.

Autonomic Nervous System

The part of the nervous system that controls the motor nerves that regulate equilibrium.

Vasoconstriction

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

Vasodilation

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

Atherosclerosis

A degeneration of blood vessels caused by the buildup of plaque in the inner wall.

Arteriosclerosis

Hardening of the arteries that cause the blood to flow less efficiently.

Consequences of Arteriosclerosis

Can narrow arteries and can cause heart attacks.

Blood Clots

Can form in narrowed or blocked arteries.

Heart Disease Statistics

Every year, heart disease affects millions of people.

Heart Disease Prevention

Healthy lifestyle choices are keys to prevention.

Aneurysm

An abnormal bulge in a blood vessel wall.

Common Sites for Aneurysm

Most common sites include the aorta and brain.

Causes of Aneurysm

Most commonly caused by high blood pressure.

Aneurysm Consequence

An aneurysm in the brain can cause a stroke.

Signs of Stroke

Weakness, trouble speaking, vision problems, headache, dizziness.

Stroke Response

If you experience any of these symptoms, CALL 9-1-1 or your local emergency number immediately.

Capillaries

Red blood cells must travel through capillaries in single file.

Capillary Thickness

Only one cell thick.

Capillaries

Site of exchange between blood and body cells.

Capillary Beds

Capillary beds are networks of capillaries that facilitate exchange.

Oxygen Rich Blood

Oxygen rich blood appears bright red.

Oxygen Poor Blood

Oxygen poor blood appears dark red.

Deoxygenated Blood Collection

Deoxygenated blood collects in small veins called venules and is carried back to the heart.

Veins and Venules Walls

Walls contain valves.

Venules Merging

Venules merge into larger veins.

Blood Flow Changes

As blood flows from arteries to arterioles to capillaries, blood flow decreases and blood pressure in these smaller vessels drops.

Pressure Insufficiency

The pressure is not great enough to push blood back to the heart.

Veins Structure

Veins have valves, steering blood back to the heart.

Skeletal Muscles Role

Skeletal muscles aide in blood flow in veins by contracting and directing blood flow toward the heart.

Layers of the Heart

The layers of the heart include the pericardium (sac around the heart for protection), myocardium (middle layer, cardiac muscle), and endocardium (inside layer, protective).

Electrical Conduction of the Heart

Heartbeat

Heart Sounds

LUB - slamming of atrioventricular valves (tricuspid & bicuspid valves); DUB - slamming of semilunar valves (pulmonary & aortic s.l valves).

Intrinsic Heartbeat

Heart beats intrinsically (autonomously - not stimulated by external nerves - will continue to beat outside of the body for a short period on its own).

SA Node

Heart rhythm set by the SA node (sinoatrial node) in the upper right atrium - also called the 'natural pacemaker'.

Nerve Stimulation of SA Node

The vagus nerve stimulates the SA node. Sympathetic nervous system stimulation will speed it up and parasympathetic nervous stimulation will slow it down.

AV Node Function

Electrical impulse travels to the AV node (atrioventricular node) which causes contraction of the ventricles.

Impulse Conduction Pathway

Then the impulse is passed along to the bundle of His, then to the Purkinje fibers which super conduct the impulse through the ventricles.

Tachycardia

Tachycardia - SA signals speed up, resulting in an increased heart rate.

Bradycardia

Bradycardia - SA signals slow down, resulting in a decreased heart rate.

Pacemaker

Pacemaker - device to help set the heart rate.

Blood Pressure Definition

Any fluid confined in a vessel (hose or vein) exerts a push against the walls that contains it (blood pressure).

Narrowing of Blood Vessel

If the blood vessel narrows, the pressure of the fluid increases.

Expanding Blood Vessel

If the blood vessel expands in diameter, the pressure inside it decreases.

Increased Blood Volume Effect

If the volume of blood goes up, pressure will increase.

Decreased Blood Volume Effect

If you lose blood volume (bleeding), pressure will decrease.

Blood Pressure Facts

Blood pressure is highest at the heart and decreases as you move away from it.

Heart Rate Factors

Any factor that speeds your heart rate will increase blood pressure.

Arteries Control BP

Your arteries can control blood pressure by changing diameter according to your body's need.

Blood Pressure

Affected by cardiac output and vessel diameter.

Normal BP

Around 110/70-120/80.

Systolic Pressure

The pressure in the arteries during heartbeats.

Diastolic Pressure

The pressure in the arteries when the heart rests between beats.

High blood pressure readings

Readings above the normal range.

Low blood pressure readings

Readings below the normal range.

Hypertension

High blood pressure risk factors.

Blood Pressure Regulation

Regulated by the medulla oblongata in the brain.

Low BP Effects

Reduces capacity to transport oxygen in tissues.

High BP Effects

Over time it damages artery and capillary walls.

Blood Pressure Negative Feedback Loop

A mechanism to maintain BP within normal range.

Blood Pressure Receptors

Found in the walls of arteries, sensitive to pressure.

Medulla Oblongata

Sends messages to lower heart rate when BP is high.

Arterioles

Will dilate when BP is too high.

Heart Rate

Number of beats per minute, affected by nerve stimulation and hormones.

Cardiac Output

Amount of blood pumped by the heart per minute.

Stroke Volume

Amount of blood pumped with each beat (~70 ml per beat).

Cardiac Output Formula

Cardiac Output = Stroke Volume X Heart Rate.

Patrick's Cardiac Output

150 beats per minute at 70 ml per beat results in 10500 ml/min.

Thermoregulation

Maintenance of body temperature.

Normal Body Temperature

Approximately 37℃.

Hypothalamus

Regulates body temperature.

Sweating Mechanism

Sweat evaporates, cooling the body.

Vasodilation

Blood vessels near the surface widen to release heat.

Cold Temperature Response

Blood vessels constrict to reduce heat loss.

Goosebumps

The response of body hairs standing on end due to nerve messages from the hypothalamus.

Heat loss prevention

Heat is trapped under the hairs, helping to reduce heat loss, most effective with hairy animals.

Rhythmic contractions

Contractions initiated by the hypothalamus that help in thermal energy regulation.

Capillary Fluid Exchange

The process where capillaries provide cells with nutrients and are associated with fluid exchange between blood and tissue.

Blood circuit

The path blood travels, starting from arteries.

Capillary blood flow

Blood moves through capillaries very slowly, allowing time for material exchange.

Diffusion

The process by which water, sugar, amino acids, wastes, hormones, and vitamins move in and out of capillaries.

Osmotic pressure

The pressure that moves water from tissue fluid into blood, with a constant of 25 mm of Hg.

Blood pressure

The pressure that moves water from blood into tissue fluid, ranging from 35-40 mmHg at the arteriole end to 10-15 mmHg at the venule end.

Outward flow of water

The movement of water and small mineral ions out of the capillaries.

Selectively permeable

A characteristic of capillaries that allows certain substances to pass through while blocking others.

Fluid movement regulation

The process by which large proteins draw water back into the capillaries.

Fluid movement into capillaries

The process known as reabsorption.

Concentration of solutes

The level of solutes in the blood that can affect fluid movement.

Lymphatic System

A system that captures excess fluids leaked from capillaries and returns proteins to the bloodstream.

Lymph

Fluid that is collected from excess fluids leaked from capillaries and products of fat digestion.

Lymphatic vessels

Vessels that capture excess fluids and transport lymph, flowing one way only.

Lymph nodes

Masses of lymphatic tissue found at intervals along lymph vessels.

Lymphocyte

A type of white blood cell involved in the immune response.

Red Bone Marrow

The tissue where blood cells are produced.