circulatory system

circulatory system

-Brings air into respiratory system

-Provides gas exchange for circulatory system

-These two systems supply cells throughout the body, with the nutrients and oxygen they need to stay alive

-basically a pump (heart), network of tubing (blood vessels) and fluid (blood)

-moves oxygen, carbon dioxide, glucose, hormones, waste products, and lipids around the body

the heart

-almost entirely muscle

-hollow organ, about the size of your fist

-enclosed by a protective sac called the pericardium

-contracts on avg 72X /min

-pumping about 70mL's per beat

septum

-divides the left and right sides of the heart

-prevents mixing of blood between chambers under high pressure

atria

-top chambers

-smaller

-less muscular

ventricles

-bottom chambers

-larger

-more muscular

blood fllow

-pulmonary circuit: blood travels through the pulmonary valve into the pulmonary artery, then to the lungs for gas exchange

-systemic circuit: blood travels through the aortic valve into the aorta to the rest of the body

atrioventricular valves

-atria from ventricles

-tricuspid (right side)

-mitral (left side)

semilunar

-ventricles and blood vessels

-pulmonary - on the way to the lungs

-aortic - on the way to the aorta

heartbeat

-two networks of muscle fibers, one in the atria and one in the ventricles, coordinate the heart's pumping action

-Varies depending on body's need for oxygen or need to release carbon dioxide

-Autonomic system of the nervous system controls heart rate

-Sympathetic system increases heart rate ("fight or flee")

-Parasympathetic system decreases heart rate ("rest and digest")

-Contraction in the Atria forces blood to the ventricles

-Contractions of the ventricles forces blood out of the heart

sinoatrial (SA) node

-Group of cardiac fibers in the right atrium starts the contraction

-When SA node fires, electrical impulse spreads through the muscle fibers in the atria and contract

-Also called the "pacemaker" because it sets the pace for the heart

atrial fibrillation

-heart's upper chambers (atria) contract randomly and sometimes so fast that the heart muscle cannot relax properly between contractions

-Reduces the heart's efficiency and performance

-Happens when abnormal electrical impulses suddenly start firing in the atria

blood vessels

-Blood leaving left side of the heart is loaded with oxygen from lungs

-Passes through the Aorta, throughout the body

-moves through 3 types of vessels (arteries, capillaries, veins)

artery

-carries blood away from the heart

-Blood is under pressure, have thick, muscular walls that regulate their diameters to regulate blood flow

-Get smaller as they move from the heart and branch into arterioles and, ultimately, capillaries

capillaries

-smallest blood vessels

-Site of exchange between blood and tissues

-Oxygen and nutrients (glucose) leave blood

-CO2 and wastes leave tissues and enter blood

veins

-carries blood toward the heart

-Less pressure, skeletal muscles provide movement

-Contain valves to prevent backflow

-Less muscular than arteries, and often found in skeletal muscle

blood pressure

-Like any pump, the heart produces pressure

-Heart contracts 🡪 a wave of fluid pressure on the arteries 🡪 known as blood pressure (BP)

-BP decreases when the heart relaxes

-Without pressure the blood would stop flowing

sensory receptors

-maintain blood pressure

-at several places in the body, measures blood pressure

-If pressure is unsafe, messages are sent to the medulla oblongata and the brain stem

-if too high, the autonomic nervous system Neurotransmitters are released to relax smooth muscle walls of arteries

kidneys

-maintain blood pressure

-Hormone produced by the heart and other organs cause kidneys to remove water from blood when pressure is too high, this reduces the pressure (diuretics)

how is blood pressure measured?

-using a sphygmomanometer

-Measures two numbers (systolic and diastolic)

-Typical reading 120/80

systolic

-Top number

-The force felt in arteries when ventricles contract

diastolic

-Bottom number

-Force felt when ventricles relax

Atherosclerosis

-one of the leading causes of heart disabilities in the U.S.

-a result of plaque build up in the arteries

-In coronary arteries (blood to heart muscle), part of heart muscle can die (heart muscle also requires oxygen)

-Can cause heart attack after time

-Stroke can occur if a clot is formed from fatty build up, it breaks loose, can cause lack of oxygen to brain

-heart must work harder

Congenital Heart Defects (CHDs)

-Conditions present at birth

-can affect the structure of a baby's heart and the way it works

-the most common

type of birth defect

Atrial Septal Defect (ASD)

-ASD is a hole between atrial (upper) chambers, a fairly common heart defect present at birth

-Oxygenated blood escapes from the left to the right atrium

-Too much blood is pumped to the lungs, lungs can't convert enough oxygen

-Small ASDs may close on their own

-Larger holes make the right pumping chamber work harder

Ventricular Septal Defect (VSD)

-VSD is a hole between ventricles (lower) chambers, a fairly common heart defect present at birth

-Oxygenated blood escapes from the left ventricle into the right ventricle and into the lungs

-This forces the heart and lungs to work harder

Pulmonary Artery Stenosis

-Narrowing of the pulmonary artery, the large blood vessel that takes blood from the right ventricle of the heart to the lungs

-This narrowing may force the heart to pump harder, leading to an enlarged heart and high blood pressure in the right side of the heart

heart rate

-gives you a measurement of beats per minute (BPM)

EKG (or electrocardiogram)

-measures the electrical activity (of heart rate)

-more dimensions to the rhythm

-provides a more indepth picture of the heartbeat and potential defects

-If the test is normal, it should show that your heart is beating at an even rate of 60 to 100 bpm