The Transport System

Transport oxygen, nutrients, and other substances throughout the

body

Removes waste from tissues

The HeartMyocardium – heart muscle• Pumps blood through the circulatory system• Designed as a pair of side-by-side pumps

The Heart• The heart is divide into 4 chambers

Atrium – Receives blood

Ventricle – Pumps blood out of the heart

Blood Flow

From the heart:• Blood enters a large artery• To smaller artery branches• To arteriole (smallest artery)• To a capillary bed• To a venule (smallest type of vein)• To larger veins• To a large vein which takes blood back to the

heart to be pumped out once again

Blood Flow Through the Heart• Blood from the body enters the heart through the right

atrium, then to the right ventricle • Pulmonary Circulation – blood picks up oxygen and

releases carbon dioxide • Blood from the lungs enter through the left atrium• Systemic Circulation – flow of blood from the heart to the

rest of the body

Aorta – the artery that emerges from the heart

Blood Flow Through the Heart

Blood Flow Through the Heart

Valves – flaps of connective tissue located

between the atria and the ventricles• When blood moves from the atria to the ventricles those

valves open• When the ventricles contract valves close

Pulmonary Circulation• Blood cell enters the Right Atrium

• Blood cell is deoxygenated • After blood pools in the Right Atria it flows through the Right

Atrio-ventricular Valve to the Right Ventricle• Right Atria contracts to push remaining blood out to the Right

Ventricle• Once the volume of blood accumulates in the Right Ventricle

it contracts• During contraction the AV valve closes to prevent backflow• Blood pressure in the Right Ventricle opens the Right

Semilunar Valve allows blood to enter the pulmonary artery

Pulmonary Circulation• Blood enters a lung continues to move along smaller and

smaller arteries• Arteriole – the smallest of arteries

• Arteriole leads to a capillary bed• Capillaries walls are one cell think which allows for gas

transfer • Blood cell gives up carbon dioxide and takes a oxygen

molecule • Blood cell returns to the heart• Pulmonary veins take the now oxygenated blood back to the

heart

Systemic Circulation

• The same red blood cell example used in the pulmonary circulation is used here.

• Blood enters the Left Atria and in unison with the right atria blood seeps to the left ventricle

• Both atria contract, blood enters ventricles (in this example Left Ventricle through the Atrio-ventricular valve)

• Left Ventricles contract (Notice the Left Ventricle is thicker than the Right Ventricle)• When this occurs Atrio-ventricular valve closes to prevent

backflow• Increase in blood pressure in the Left Ventricle opens the

semilunar valve and allows blood through the aorta• Blood leaves the heart through the aorta

Systemic Circulation• Blood then goes into one of 2 pathways

1. Through the body system eventually to capillary beds to pass on oxygen and nutrients

2. The Hearts Blood Supply• The heart needs a constant supply of oxygen and

nutrients• It gets very little from the blood it pumps

Coronary Arteries – a pair of blood vessels which branch

from the aorta and run through the

heart tissue

Circulation

For the record:

• Blood is never Blue!• Blue represent deoxygenated blood: NO IT IS NOT

BLUE!!!• More like a dark verses a bright red

Control of Heart Rate

Cardiac Muscle – muscle tissue specifically

located in the heart

Myogenic Activity – the ability of cardiac muscle to

contract and relax without

nervous system control• This myogenic activity needs to be controlled in

order to keep the timing of the contractions to be unified and useful

Control of Heart Rate

Sinoatrial Node (SA Node)• Mass of tissue within the Right Atria• This is known as the pacemaker for the heart• SA Node sends an electrical signal to initiate

contraction to both atria• At 72 beats per min that is a signal every .8

seconds

Control of Heart RateAtrioventricular Node (AV Node)

• Receives signal from SA Node• Waits .1 seconds then sends another electrical

signal• This signal goes to the ventricles• So first the Atria contracts then the Ventricles

Heart Rate

• Heart Rate varies depending on your bodies needs.• During exercise your heart rate could increase to 200

beats per min.

Heart Rate• Heart rate is controlled as a result of carbon dioxide

levels in the blood• As carbon dioxide increases an area in the brain stem

the medulla chemically senses the levels• Medulla sends signal through a cranial nerve (AKA

Cardiac Nerve)• This increases the heart rate to an appropriate level

• This signal is sent to the SA Node• It does not change the mechanism of how the heart

beats just the timing

Heart Rate• AS CO2 returns to normal a signal is sent for the medulla

through the Vagus Nerve to return the heart rate to normal.

Adrenaline – a chemical released by your adrenal

glands during periods of high stress

or excitement. (AKA – Epinephrine)• Adrenaline causes the SA Node to fire more frequently,

increasing the heart rate

Blood Vessels

Blood Vessels

Arteries• Large Vessels that carry blood from the heart to

the tissues of the body.• Pulmonary arteries are the only ones that

carry blood poor in oxygen.• The rest carry oxygen rich blood

• They have thick smooth muscle layers used by the autonomic nervous

system to change the

diameter of the vessel• This regulates blood

pressure

Blood Vessels• From the arteries to the arterioles to the capillary bed.

Capillary Bed – a network of capillaries that typically all

drain into a single venule• When blood enters the capillary bed much of the

pressure is lost • Blood cells make it through the capillaries one cell at a

time

Blood Vessels

Capillaries• Smallest Blood Vessels• Thin walls allow for oxygen and nutrients to

diffuse from the blood to the tissue• Also CO2 and waste diffuse from tissue to blood

Blood Vessels

Veins• Returns blood to the heart from the

capillaries• Blood returns to the heart usually against

gravity• Skeletal muscle help “push” blood towards

the heart.• Valves prevent back flow• Blood pressure is low causing

blood flow to be slow

Components of Blood

Plasma – liquid portion of blood

Erythrocytes – red blood cells

Leucocytes – white blood cells (phagocytes and lymphocytes)

Platelets – cell fragments (assists in blood clotting)

Transport by Blood

Nutrients – glucose, amino acids, etc

Oxygen – reactant for aerobic cell respiration

Carbon Dioxide – waste produce of aerobic cell repiration

Hormones – transported from gland to target cells

Antibodies – protein molecules involved in immunity

Urea – nitrogenous waste (filtered out of the blood by the

kidneys’s)

Heat – Skin arterioles (can change diameter in order to

gain or lose heat)

Blood Pressure

• When the heart contracts it produces a wave of fluid pressure in the arteries

• Pressure decreases when the heart relaxes• System still remains under pressure due

to elasticity of the arteries• Pressure allows blood to continue to flow

through the arteries.

Blood Pressure

Sphygmomanometer • Device that measures blood pressure • Typical blood pressure in a healthy adult is

120/80• Top Number: Systolic• Bottom Number: Diastolic

Blood Pressure Lab• Record in your composition book

Step 1 - Choose the right equipment: 1. A quality stethoscope 2. An appropriately sized blood pressure cuff 3. A blood pressure measurement instrument such as an aneroid or mercury column sphygmomanometer or an automated device with a manual inflate mode.

Step 2 - Prepare the patient: Make sure the patient is relaxed by allowing 5 minutes to relax before the first reading. The patient should sit upright with their upper arm positioned so it is level with their heart and feet flat on the floor. Remove excess clothing that might interfere with the BP cuff or constrict blood flow in the arm. Be sure you and the patient refrain from talking during the reading.

Blood Pressure Lab

Step 3 - Choose the proper BP cuff size: Most measurement errors occur by not taking the time to choose the proper cuff size. Wrap the cuff around the patient's arm and use the INDEX line to determine if the patient's arm circumference falls within the RANGE area. Otherwise, choose the appropriate smaller or larger cuff.

Step 4 - Place the BP cuff on the patient's arm: Palpate/locate the brachial artery and position the BP cuff so that the ARTERY marker points to the brachial artery.  Wrap the BP cuff snugly around the arm.

Step 5 - Position the stethoscope: On the same arm that you placed the BP cuff, palpate the arm at the antecubical fossa (crease of the arm) to locate the strongest pulse sounds and place the bell of the stethoscope over the brachial artery at this location.

Blood Pressure Lab

Step 6 - Inflate the BP cuff: Begin pumping the cuff bulb as you listen to the pulse sounds. When the BP cuff has inflated enough to stop blood flow you should hear no sounds through the stethoscope. The gauge should read 30 to 40 mmHg above the person's normal BP reading. If this value is unknown you can inflate the cuff to 160 - 180 mmHg. (If pulse sounds are heard right away, inflate to a higher pressure.)

Step 7 - Slowly Deflate the BP cuff: Begin deflation. The AHA recommends that the pressure should fall at 2 - 3 mmHg per second, anything faster may likely result in an inaccurate measurement. 

Blood Pressure Lab

Step 8 - Listen for the Systolic Reading: The first occurence of rhythmic sounds heard as blood begins to flow through the artery is the patient's systolic pressure. This may resemble a tapping noise at first.

Step 9 - Listen for the Diastolic Reading: Continue to listen as the BP cuff pressure drops and the sounds fade. Note the gauge reading when the rhythmic sounds stop. This will be the diastolic reading.

Blood Pressure Lab

Step 10 - Double Check for Accuracy: The AHA recommends taking a reading with both arms and averaging the readings. To check the pressure again for accuracy wait about five minutes between readings. 

• Typically, blood pressure is higher in the mornings and lower in the evenings.