The Cardiorespiratory System

What does blood do?

1. Transportation / Distribution

Carries oxygen, nutrients, hormones, and remove wastes

2. Defense

Protects you from germs and diseases (WBCS and blood clots)

3. Homeostasis (keeping balance)

Helps control body temperature, pH, and fluid balance

Red Blood Cells (RBCs / Erythrocytes)

Carry oxygen using hemoglobin

Give blood its red color

White Blood Cells (WBCs / Leukocytes)

Fight infections

Part of the immune system

Neutrophils- first to respond to a bacteria or virus

Eosinophils- allergy

Basophils- asthma

Lymphocytes- produce antibiotics

Monocytes- clean up dead cells

Platelets (Thrombocytes)

Help blood clot

Stop bleeding when you get a cut

Where Are Red Blood Cells Made?

Made in the bone marrow

The body makes more RBCs when oxygen levels are low

The kidneys release a hormone called erythropoietin to tell the body to make more RBCs

BLOOD TYPES (ABO SYSTEM)

Antigens = blood type (A, B, AB, or O) is determined by specific sugar/protein markers on your red blood cells

Antibodies = proteins in plasma that attack foreign antigens

ABO Blood Types

Blood Type	Antigens on RBCs	Antibodies in Plasma
A	A	Anti-B
B	B	Anti-A
AB	A & B	None
O	None	Anti-A & Anti-B

Why Is Type O the Universal Donor?

Type O has NO antigens

No antigens = nothing for antibodies to attack; its cells lack markers to trigger a reaction in others.

Why Can Type O Only Receive Type O?

They have both antibodies

Other blood types would be attacked

Why Is Type AB the Universal Receiver?

Type AB has NO antibodies

Can receive blood from any type

Why Can Type AB Only Donate to AB?

Their blood has both antigens

Other blood types would attack it

RH FACTOR

Rh+ = has Rh antigen

Rh- = no Rh antigen

Rh- people can only receive Rh- blood

Layers of the Heart (Outside → Inside)

1. Pericardium – protective sac

2. Epicardium – outer heart layer

3. Myocardium – muscle (does the pumping!)

4. Endocardium – smooth inner lining

Blood Flow Through the Heart

1. Superior & Inferior Vena Cava

2. Right Atrium

3. Tricuspid Valve

4. Right Ventricle

5. Pulmonary Arteries

6. Lungs

7. Pulmonary Veins

8. Left Atrium

9. Mitral (Bicuspid) Valve

10. Left Ventricle

11. Aortic Valve

12. Aorta

13. Body

Tip: Right side = lungs, Left side = body

Other Heart Parts

Septum – wall between right & left sides

Apex – pointy bottom of the heart

CARDIAC CYCLE

Systole = heart contracts (pumps blood)

Diastole = heart relaxes (fills with blood)

CARDIAC CONDUCTION SYSTEM (Heart’s Electrical System)

Part	What It Does
SA Node	Pacemaker (starts heartbeat)
AV Node	Slows signal
Bundle of His	Sends signal down
Bundle Branches	Sends signal to sides
Purkinje Fibers	Makes ventricles contract

EKG (Electrocardiogram)

Doctors use EKGs to:

• Check heart rhythm

• Find heart problems

EKG Waves

• P Wave – atria contract

• QRS Complex – ventricles contract

• T Wave – ventricles relax

BLOOD PRESSURE

Systolic (top number) = pressure during contraction

Diastolic (bottom number) = pressure during relaxation

BLOOD VESSELS

Types of Blood Vessels

Vessel	Job	Features
Arteries	Away from heart	Thick walls
Veins	To heart	Valves
Capillaries	Exchange	Thin walls

Capillaries allow gas exchange because they are one cell thick

MAJOR BLOOD VESSELS

Carotid Artery – neck/brain

Jugular Vein – neck

Subclavian V/A – shoulders

Brachial Artery – upper arm

Basilic Vein – arm

Aorta – heart to the whole body

Pulmonary Artery/Vein – lungs

Renal V/A – kidneys

Hepatic V/A – liver, pancreas, duodenum

Gastric V/A – stomach

Iliac V/A – hips

Femoral V/A – thigh

Superior & Inferior Vena Cava – return blood to the heart

What Do Kidneys Do?

Filter waste from blood

Balance water & salts

Control blood pressure

Help make RBCs

Parts of the Kidney

Part	Job

Renal Cortex

Outer layer

Medulla

Inner layer

Minor Calyces

Collect urine

Major Calyces

Move urine

Ureter

Carries urine to bladder

Renal Capsule

Protects kidney