• Why do we need a circulatory system?

– supplies in• fuel (sugars)

– digestive system• oxygen

– respiratory system– waste out

• CO2

– respiratory system– need to pick up & deliver

the supplies & wastes around the body

• circulatory system

Complex organisms

• Circulatory system – made up of 3 parts

• organ– heart

• tissues & cells– blood vessels

» arteries» veins» capillaries

– blood» red blood cells» plasma

Vertebrate Heart

• 4-Chambered heart– atria (atrium)

• thin wall• collection chamber• receive blood

– ventricles • thick wall pump• pump blood out

rightatrium

leftatrium

rightventricle

leftventricle

• 2 part system– Circulation to lungs (pulmonary)

• blood gets O2 from lungs

• drops off CO2 to lungs

• brings O2-rich blood from lungs to heart

– Circulation to body (systemic)

• pumps O2-rich blood to body

• picks up nutrients from digestive system

• collects CO2 & cell wastes

Circulation of Blood

heart

lungs

body

Circulationto lungs

Circulationto body

Circulation of Blood

•Systemic Circulation – to body tissues(Deliver: oxygen & nutrients. Pick up: carbon dioxide & waste)

•Pulmonary Circulation – to lungs (for Gas Exchange)

left ventricle aorta arteries arterioles capillaries venules veins vena cava right atrium

right ventricle pulmonary artery capillaries (at alveoli in lungs) pulmonary vein left atrium

SystemicCirculation

PulmonaryCirculation

Oxygenated BloodDeoxygenated Blood

Pacemaker (SA node)

• Sinoatrial node (pacemaker), located in the right atrium, generates impulses for heart muscle contraction.

Blood vessels

arteries

arterioles

capillaries

venules

veins

artery

arteriolesvenules

veins

Arteries

• Blood vessels that carry blood away from the heart

• Aorta is the largest Artery

• Arterioles are smaller Arteries that deliver blood to capillaries

Veins

• Vessels that return blood to the heart from the local tissues

• Vena Cava is the largest vein

• Pulmonary veins carry oxygenated blood from the lungs to the heart

• Venules are smaller veins that bring blood away from capillaries

Closed valve

Open valve

Capillaries

• Capillaries– very thin walls – allows diffusion of materials

across capillary

• O2, CO2, H2O, food, waste

body cell

O2

food

waste

CO2

Blood Pressure

• The amount of force blood places against artery walls

• Systolic Pressure: pressure when the heart contracts (top number)

• Diastolic Pressure: pressure when the heart relaxes (bottom number)

• Average adult BP is 120/80

if systolic > 150or

if diastolic > 90

Cardiovascular healthbypass surgery• Risk Factors

– genetics– diet

• high animal fat– exercise &

lifestyle• smoking• lack of

exercise

normal

hardening of arteries

Blood & blood cells

• Blood is a tissue of fluid & cells– plasma

• liquid part of blood• dissolved salts, sugars, proteins, and more

– cells • red blood cells (RBC)

– transport O2 in hemoglobin

• white blood cells (WBC)– defense & immunity

• platelets– blood clotting

RBCs• Transport Oxygen• Contain

Hemoglobin: oxygen carrying protein

WBCs• Protect and fight

against infection• Critical component

of the immune system

Platelets• produce thread-

like fibers which trap blood parts

• Responsible for clotting

Hemoglobin

• Protein which carries O2

– 250,000 hemoglobins in 1 red blood cell

O2

O2O2

O2

Blood clotting

protein fibersbuild the clot

emergency repair of circulatory system

plateletsseal the hole

chemicalemergencysignals

Why do we need a respiratory system?

• Need O2 in

– for cellular respiration– make ATP

• Need CO2 out

– waste product

O2

food

ATP

CO2

alveoli

Air passage way: Pharynx larynx trachea bronchi bronchioles alveoli

Important Structures

• Epiglottis- a flap of tissue that closes over the trachea when swallowing

• Larynx- “voice box” containing vocal cords

• Trachea- the windpipe

• Bronchi- passages through which air spreads through the lungs

Structure

• Lungs: contain networks of bronchi that lead to tiny sacks called alveoli where gas exchange occurs

Moving gases into/out bloodstream

• Inhale

– O2 passes from alveoli to

blood by diffusion

• Exhale

– CO2 passes from blood to

alveoli by diffusion

Negative pressure breathing

• Air flows from higher pressure to lower pressure, rushing into the lungs

inhale exhale

Medulla oblongata controls breathing

• Medulla oblongata monitors CO2 level of blood

– It measures pH of blood (CO2 + H2O H2CO3 carbonic acid

• if pH decreases then increase depth & rate of breathing & excess CO2 is eliminated in exhaled air

Emphysema

• A disease that progressively destroys the walls of alveoli most commonly caused by smoking.

Breathing and Homeostasis

• Homeostasis– keeping the internal environment of the

body balanced

– need to balance O2 in and CO2 out

– need to balance energy (ATP) production• Exercise

– breathe faster• need more ATP

• bring in more O2 & remove more CO2

• Disease– poor lung or heart function = breathe faster

• need to work harder to bring in O2 & remove CO2

O2

ATP

CO2