Anatomy/Physiology
Circulatory System
Purpose: closed system carrying blood around body, supplying cells with O2 and
nutrients while removing waste.
Main Components: Heart, arteries, capillaries, veins and blood; the lymphatic system is
closely related.
1. Heart:
a. Muscular pump- lies within the pericardium
b. 4 chambers: an atrium or auricle (upper) and a (lower) ventricle on each
side of the muscular septum dividing the heart lengthwise
c. Auricles receive blood from veins; Ventricles pump blood into arteries
d. Valves control blood flow (volume) in and out of heart
2. Arteries:
a. Branching blood vessels taking blood from heart to body tissues
b. Aorta = main artery
c. Arterioles are tiny arteries regulating blood supply to capillaries
3. Veins:
a.
b.
c.
d.
e.
Blood vessels transporting blood to the heart.
Valves ensure blood flows only one way
Superior/Inferior vena cava are the largest veins
Venules- smallest veins taking blood from capillaries
Venous sinuses drain blood from the brain
4. Capillaries:
a. Minute tubes linking arterioles with venules.
b. Exchange substances with nearby tissues via capillary cell walls
5. Blood:
a. COMPLEX!!
b. Major components: plasma, erythrocytes (red cells), leucocytes (white
cells) and platelets.
c. Blood grouping- dependent on the presence (absence) of agglutinins (A or
B)
6. Bone Marrow:
a. Tissue in bone producing erythrocytes, and leukocytes (called
granulocytes and monocytes)
7. Spleen:
a. Located below diaphragm
b. Stores and releases erythrocytes and eliminates damaged erythrocytes
while producing lymphocytes.
8. Lymphatic System:
a. Contains lymph- a colorless fluid likely derived from blood
b. Lymph nodes- enlargements that produce bacterial lymphocytes
c. Draining lymph nodes: Cervical nodes (neck), axillary nodes (arm pits),
cubital nodes (radial-humoral joint), abdominal nodes (below xyphoid
process), inguinal nodes (lower groin), pelvic nodes (hips and in) and
popliteal nodes (behind knees).