Human Anatomy 205

Cardiovascular & Lymphatic Systems

[Blood] [Heart] [Blood Vessels] [Lymphatic System] [Lab Models] [Practice tests]

Visit Anatomy of Heart and Circulatory System at Texas Heart Institute

Function of Circulatory System

Transport [respiratory gases, nutrients, metabolic wastes, hormones]
Protection
- phagocytic leucocytes
- immunity - lymphocytes
- clotting - platlets

Blood is the circulating fluid composed of plasma + formed elements

Hematocrit separates blood in a tube by centrifugation into:
1. 55% Plasma a straw colored fluid
2. Formed elements [buffy coat, (<1% leucocytes and platelets)]
3. Formed elements [45% erythrocytes]
Plasma is water + solutes [proteins, nutrients, waste, electrolytes, gases, buffers]
Serum = plasma minus clotting factors (fibrinogen)
Formed elements of the blood [erythrocytes, leucocytes, platelets]
- See illustration
- See microscopic view interactive blood cells
- Hemopoiesis the fomation of blood cells from stem cells of red bone marrow

Erythrocytes make up about 45% of blood
- Erythropoiesis forms erythrocytes in red bone marrow
- Cells are biconcave discs lacking nuclei.
- Almost entire weight is hemoglobin.
- About 98% of O₂ and 8% of CO₂ are transported on hemoglobin .
Leucocytes function in body defense and immunity
- Granulocytes are leucocytes the with cytoplasmic granuals.
  - Three types of granulocytes: [neutrophils, eosinophils & basophils ]
  - LMC histology lab slide [Neutrophil]
  - Neutrophils and lymphocyte
- Agranulocytes are leucocytes without cytoplasmic granuals
  - [lymphocytes and monocytes]
  - Lymphocytes function in immune process
  - See how lymphocytes produce antibody.
  - LMC histology lab slides [Lymphocyte] [Monocyte]
Platelets (Thrombocytes) function in hemostasis (clotting)
- Start the production of blood clotting
- Hemostasis prevents blood loss.
- Production of platelets is thrombopoiesis

Heart is muscular, parallel pumps (right and left)

Right receives deoxygenated blood and pumps to lungs

Left receives oxygenated blood from lungs and pumps to body organs.

See heart information and graphics
Heart in pericardial cavity of thorax surrounded by pericardium [visceral, parietal]
Heart Histology Three layers
1. epicardium = visceral pericardium (outer serous epithelium)
2. myocardium, thick layer of cardiac muscle
3. endocardium, simple squamous epithelial lining chambers and valves
Heart animation
Four Heart Chambers [See interactive lab model]
- Right & Left. atria receive venous blood
- Right. & Left. ventricles pump blood into arteries
Right & Left chambers are separated by a septum [interatrial] [interventricular]
Heart Valves closing produce heart beat [lubb dubb] [Demo heart sounds]
- Semilunar valves at base of aorta & pulmonary trunk [aortic & pulmonary]
- Atrioventricular valves between atria & ventricles
  - Right AV valve [tricuspid]
  - Left AV valve [bicuspid]
  - chordae tendineae extend from AV valves to papillary muscle on walls of ventricles
The 3 Circulatory Routes through heart
(select link & click "Go" below)
Cardiac Cycle has two main phases
1. Systole = contraction of ventricles [AV Valves close]
2. Diastole = relaxation of ventricles [Semilunar Valves close]
Reviews of heart anatomy names or terms
Electrical Conduction System
- Anatomical parts [SA node, AV node, AV bundle. purkinje fibers]
- See sequence of conduction through heart
- Electrical impulse is graphed as ECG [See tutorial]

Name parts in double route through heart

click on heart gif to see interactive model

click on heart above for interactive lab model

Blood Vessels * See Tubular Circulation and major blood vessels on lab model

Blood vessel wall histology- microslide and illustration[tunica externa (adventitia)] [tunica media] [tunica interna (intima)]
See LMC histology lab slide [comparing Artery vs Vein]
Blood Pressure [Systoic and diastolic]
Arteries carry blood from heart to organs
- Arteries have thick walls and high blood pressure
- Blood is oxygenated (red) (pulmonary is exception)
- Arterial pulse detected at common carotid, radial, femoral, popliteal.
Pulmonary circuit arteries carry deoxygenated blood (blue) See [Interactive lab torso]
Major systemic circuit arteries arise from the aorta.
- See diagram of Aorta and major branches from aortic arch
- Major arteries branching from abdominal aorta
- Leg model shows Ext.Iliacs in pelvis & femorals on thigh.
- See the illustration of aorta and its major branches.
Abdominal aorta and Inferior Vena Cava See [Interactive lab model]
See circulation to brain via Circle of Willis (cerebral arterial circle)
Circle of Willis animated and explained
Arterioles control volumn of blood flow into organs
- contstriction and dilation of smooth muscles in arteriole wall
- precapillary sphincter, a ring of muscle where capllaries branch off arteriole
Capillaries join arterial blood flow to venous blood flow.
- Walls consist only of squamous epithelium [endothelium]
- Function in molecular exchange with tissues
- Interstitial fluids formed at capillaries from blood
Veins carry blood from organs to atria of heart.
- Veins have thin wall and low blood pressure
- Blood is oxygen depleted (blue)
- Many veins without companion artery and found near surface
  - great saphaenous [medial thigh and leg]
  - basilic, cephalic and median cubital [arm]
- Large viens have one-way valves
- Superior Vena Cava receives venous blood from the arms and head
- Inferior Vena Cava receives venous blood from the legs and body trunk

Fetal Circulation - know the blood flow through each of the following

umbilical arteries & vein carries fetal blood to and from placenta
ductus venosus from umbilical vein to IVC. Bypasses hepatic portal to liver
foramen ovale allows blood to pass from R.Atrium to L. Atrium
ducus arteriosus shunts blood from pulmonary trunk to aorta

Heart & Blood Vessels on LMC Lab Models

Heart [anterior view] [Interactive chambers and valves] [coronal section] [interactive posterior view]
Heart models unlabeled [right chambers revealed] [left chambers revealed] [coronal section]
Torso Heart [in thorax] [post view coronary sinus, azygos, int mammary] [superior vena cava branches]
Circulation Model [Brain stem vertebral & basilar][ major vessels] [ major vessels unlabeled] [ thigh & leg] [ upper appendage]
Pelvis, thigh and leg [ Iliacs & femorals] [ Iliacs & femorals unlabeled] [ Great Saphenous Vein][ anterior tibial]
Arm [ brachial]
SkeleTorso [ neck] [Interactive abdominal aorta, Inferior vena cava] [ radial, ulnar]
Torso vessels [Interactive Internal jugular, subclavian, coronary] [Internal jugular, subclavian, coronary] [Internal mammary] [phrenic, celiac. splenic, common iliac]
Torso (3/4) [ carotids] [ external jugular] [ thorax] [abdominopelvic vessels]
Torso (Big)[ pelvis & thigh]
Key to circulatory system anatomy on torsos and models

Crosswords Games and Practice Tests

Crosswords on [Circulatory System] [Heart Anatomy] [Blood Vessels] also on [Lympatic System & Immunity]
WebAnatomy at University of Minnesota
- Test your knowledge on quizzes: cardiovascular System
- WebAnatomy games: [heart], [heart conduction system ] [blood vessels associated with heart], [major arteries], [major veins]
Play Quia [ Human Circulatory System] [cardiovascular & lymphatic system]
Trace the path of blood through the circulatory system. click link to check answers
- List in order the major blood vessels and heart chambers to travel from:
- Hint: Organ to heart in vein, heart to organ in artery, always must pass through lungs

Lymphatic System

Fluid escaping from the blood at the capillaries is Interstitial fluid
Lymph is interstitial fluid within the lymphatic vessels
Lymph is returned to the blood by the lymphatic system.
Lymphatic vessels start as lymph capillaries
Thoracic Duct & Right Lmyphatic Duct are main lymphatic vessels.
Lymph is returned to R. & L. Subclavian Veins by Thoracic Duct & Right Lmyphatic Duct.
Lymph nodes are bodies or specialized swellings along lymph vessels
Cross section of lymph node
Some of the principle regions of lymph node clusters are cervical, axillary and inguinal
Other lymphoid organs [thymus] [tonsils] [spleen ]
Lymphocytes are organized in lymphoid tissue and function in immunity.

IMMUNITY

Lymphocytes are immunity cells and monocytes are phagocytic.
Lymphocytes produce protein molecules that recognize antigens and bind to them.
- Antibodies are secreted by B-lymphocytes and circulate in blood plasma and bind to antigen
- Receptors on the T-lymphocyte surface bind to antigen on infected cell surface
When stimulated by antigen lymphocytes produce clones of immunity cells and memory cells.
Antigens are proteins foreign to the body.
Antigens stimulate Lymphocytes (both B-cells & T-cells) to form clones that produce proteins that specifically bind to the antigen.
Two classes of lymphocytes [B-cells & T-cells] provide a dual immunity.
- Humoral immunity from B-lymphocytes; cellular immunity from T-lymphocytes
- Table comparing B & T lymphocyte action
- Animation of B & T lymphocyte action
B-lymphocytes produce clones of plasma cells and memory cells
- Each B-cell programmed to produce only one specific antibody
- Plasma cells secret antigen specific antibodies.
- Memory cells can respond to later occurence of antigen and are responsible for humoral immunity.
- See how lymphocytes produce antibodies
- See B-cells to antibodies
T-lymphocytes
- produce antigen specific receptors on its cell surface.
- responsible for cell-mediated immunity.
- produce clones of Helper T's (CD4), Killer T's (CD8) and memory T's
- T-cells produce lymphokines ( cytokines) for cell to cell communication

Cardiovascular Anatomy
Texas Heart Institute

Dynamic Human
at McGraw-Hill

Human Anatomy
Online

Etymology of
Medical Terms

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