Chapter 32: Circulation and Cardiovascular systems

Function of the Circulatory System

Moves fluids between various parts of the body

How do Invertebrates without a circulatory system function?

Each cell is exposed to water and can exchange gasses and eliminate wastes

Invertebrates without a circulatory system

• sponges

• Cnidarians

• Flatworms

How does the dependency on the body cavity differ between pseudocoelomates and coelomates?

While both use their body cavities for circulation, a coelomate also depends on it for locomotion

Hemolymph

Mix of blood and interstitial fluids in body cavity

Open Circulatory system

Heart pumps hemolymph into the body cavity, bathes the internal organs, then drains back into the heart

Closed Circulatory System

Heart pumps blood into the capillaries, gases and materials diffuse to and from nearby cells, then vessels return blood back from heart.

Examples of Closed Circulatory System

• arthropods

• Mollusks

Examples of Open Circulatory System

• Earthworms

• Cephalopods

All vertebrates have a ______ circulatory system

Closed

Atria

Receive blood from general circulation

Ventricles

Pump blood out through blood vessels

Arteries

Carry blood away from the heart

Arterioles

Small arteries that lead to capillaries

Capillaries

Exchange materials with the tissue fluid (interstitial)

Venules

Join to form a vein

Veins

Return blood to the heart

Vertebrate heart:

• Atria

• Ventricles

Vertebrate Vessels:

• Arteries

• Arterioles

• Capillaries

• Venules

• Veins

Fish

Blood flows in a single loop and have a single atrium and ventricle

Amphibians

Blood flows in a double loop and have systemic and pulmonary circuits along with two atria but a single ventricle

Most Reptiles

Have a septum dividing the ventricles and have a mix of oxygen rich or poor blood.

Birds and Mammals

Blood flows in a double loop so they’ll have two circuits. Divided heart in which right ventricle pumps blood to lungs whole the left pumps to the body.

Upper chambers of the Human Heart

• named the artia

• Thin-walled

• Receives blood

Lower chambers of the Human Heart

• named the ventricles

• Thick walled

• Pump blood away from the heart

Atrioventricular Valves

• Tricuspid (right)

• Bicuspid (left)

Semilunar valves

• Pulmonary (right)

• Aortic (left)

Steps of the Blood Flow

1. Blood drains from superior or inferior vena cava into the right atrium

2. Blood moves out of the lungs via pulmonary artery

3. Blood returns from the lungs to the left atrium through the pulmonary vein

4. Blood leaves the heart through the aorta

Pulmonary Circuit

Takes oxygen-poor blood to the lungs and returns oxygen-rich blood to the heart.

Systemic Circuit

Takes oxygen-rich blood from the heart to tissues throughout the body and returns oxygen-poor blood through the vena cava

Portal System

Blood from the capillaries go through the veins to another set of capillaries without first traveling to the heart

Systole

Contraction of the heart chambers

• ventricles filling

Diastole

Relaxation of the heart chambers

• blood pushes through tricuspid and mitral valves into resting lower ventricles

Cardiac Cycle

Two-part pumping action

SA (sinoartial) node

generates electrical impulses in atria and sets the rate of heart contractions

AV (atrioventrical) node

relays signals to the ventricles to trigger ventricle contractions

Systolic Blood Pressure

Pressure results from the blood forced into the arteries during the ventricular systole

Diastolic Blood Pressue

Pressure in the arteries during the ventricular diastole

Stationary Clot

Thrombus

Moving clot

Embolus

Atherosclerosis

Accumulation of fatty acid materials (plaque) between the inner linings of the arteries

Stroke

Disruption of blood supply to the brain

Angia pectoris

Painful squeezing sensation from myocardial oxygen insufficiency due to partial blockage of a coronary artery

Myocardial Infarction

Heart attack

Blood

Transports gases, nutrients, waste products, antibodies, and hormones throughout the body

Erythrocytes (red blood cells)

• contain hemoglobin

• Made in the bone marrow

Anemia

Not enough erythrocytes

Blood types are determined by…

Presence or absence of surface antigens

Cross reactions/ receiving wrong blood type causes..

Agglutination because antigen binds to the new bloods antibody

Hemolytic Disease

Anti-Rh antibodies cross the placenta and attack the RBC of another Rh-positive baby in a pregnancy

Leukocytes (White blood cells)

• Mostly larger than red blood cells

• Contain nucleus and lack hemoglobin

• Important in inflammatory response

Granular leukocytes

• neutrophil

• Basophil

• Eosinophil

Neutrophil

Phagocytize and digest bacteria

Basophil

Contain histamine

Eosinophil

Involved in fighting parasitic worms

Monocytes

Migrate into tissues in response to chronic, ongoing infections and differentiate into macrophages

Lymphocytes

T-cells and B-cells involved in the immune response and antibody production

Platelets

Result from fragments of megakaryocytes in red bone marrow

Water exits a capillary near the

Arterial end

Water enters a capillary near the

Venous end

Function of capillaries

Thin walls to diffuse nutrients, gasses and wastes

• O2 goes out

• CO2 goes in

Lymph

Excess interstitial fluid leaving the capillaries that is then returned into systemic venous blood