Upload
5alod
View
138
Download
0
Tags:
Embed Size (px)
DESCRIPTION
anatomy lecture 4
Citation preview
CARDIOVA
SCULAR
SYSTE
M
HEART Hollow, muscular organ 300 grams (size of a fist) 4 chambers Found in chest between lungs Surrounded by membrane called
pericardium Pericardial space is fluid-filled to
nourish and protect the heart.
HODS - Nov
embe
r 2006
2
POSITION OF THE HEART
Lies in the chest behind the sternum and between the lungs.
Coverings of the heart; Pericardium
• Pericardium-double layered sac composed of two parts: fibrous and serous membranes.
• The serous pericardium is two layers:1. Visceral pericardium form the inner layer that is on the
surface of the heart muscle.2. Parietal pericardium form the outer layer of the serous
membrane and secretes pericardial fluid
• Pericardial space is a potential space between the visceral and parietal layers of the serous membrane.
• Pericardial fluid- (serous fluid) prevents friction as the heart beats
Clinical Correlation
pericardial effusion: Inflammatory diseases can cause fluid to accumulate in the pericardial cavity.
Hemopericardium: Bleeding into the pericardial cavity.
may result from penetrating heart wounds or perforation of a weakened heart muscle following myocardial infarction.
Chambers of the heartRight Atrium• Thinner wall than ventricles• Receives deoxygenated blood from vena cava• Passes blood through tricuspid valve into right ventricleRight Ventricle• Thicker wall than atria• Comprises most of anterior surface of heart• Circulates deoxygenated blood to lungs through the pulmonary valve
into pulmonary arteryLeft Atrium• Receives freshly oxygenated blood from pulmonary vein Passes blood
to left ventricle through mitral valveLeft Ventricle• Receives blood from left atrium• Thickest myocardial wall• Forms apex of heart• Sends blood to systemic circulation via aorta
Valves of the heart
tricuspid
bicuspid(mitral)
aortic semilunar valvepulmonary semilunarvalve
posterior
Valves of the heart
posterior
aortic semilunar valvepulmonary semilunar
bicuspid(mitral) tricuspid
Layers of heart tissueEndocardium• Inner lining• Smooth surface that permits blood to move easily through the heart.
Myocardium• Middle layer made of cardiac muscle• Forms the bulk of the heart wall• Contains the septum- a thick muscular wall that completely
separates the blood in the right side of the heart from the blood in the left side.
Epicardium• Protective, outer layer of the hear• The coronary blood vessels that nourish the heart wall are located in
this layer.
The cardiac muscle (myocardium) Cardiac muscle is composed
of irregular branched cells.
Bound together longitudinally by intercalated disks.
Shows strong, involuntary contractions.
Atrioventricular Valves
• Chordae tendineae tiny collagen cords that connect cusps of valve to papillary muscles
• Atrioventricular Valves:
Left AV valve (Mitral, bicuspid)• Contains 2 cusps Right AV valve (Tricuspid)• Contains 3 cusps
CONDUCTING SYSTEM OF THE HEART
• Which initiates the electrical impulse for heart’s contraction (heartbeat) and spreads it through the ventricular myocardium.
• sinoatrial (sa) node (pacemaker) it lies in the wall of the right atrium it generate the nerve impulses
• atrioventricular (av) node lies in the lower part of the interatrial septum.
17HODS - November 2006
Deoxygenated blood returns to the heart via the superior and inferior vena cava, enters the right atrium, passes into the right ventricle, and from here it is pumped to the pulmonary artery.
Oxygenated blood returning from the lungs enters the left atrium via the pulmonary veins, passes into the left ventricle, and is then pumped to the aorta.
18HODS - November 2006
• The heart has two pumping chambers that work together, right ventricle (pulmonary) and left ventricle (systemic).
• Repetitive, sequential contraction is called systole and relaxation called diastole.
19HODS - November 2006
• Artery - vessel that carries blood away from the heart. Usually oxygenated. All arteries carry oxygenated blood except pulmonary artery.
• Vein - vessel that carries blood towards the heart. Usually deoxygenated. All veins carry deoxygenated blood except pulmonary vein.
• Capillary - a small blood vessel that connect end of the arteries and beginning of the veins
Walls of blood vessels
• Consist of three layers: tunica intima, tunica media, and tunica externa (or adventitia).
• The artery has a thicker wall and narrow lumen. • The vein has thinner wall and large lumen .
• The veins has valves.
• Capillaries have only one layer called endothelium.
22HODS - November 2006
Blood Vessels
• Systemic vessels– Transport blood through the body part from
left ventricle and back to right atrium
• Pulmonary vessels– Transport blood from right ventricle through
lungs and back to left atrium.
Blood vessels of the heart
Coronary Arteries supply the heart wall with oxygenated blood Cardiac Veins remove deoxygenated blood from the heart wall
LYMPHATIC SYSTEMS
Lymphoid organs include:
• Lymph nodes
• Spleen
• Thymus
• Tonsils
Function:Host defense; eliminates abnormal (sick, aged, or cancerous) cells and pathogens.
The Lymph
plasma from capillaries pass out to the space between the cells to supply the cells with oxygen and nutrient and remove carbon dioxide and waste products.
85% plasma that moved out of capillaries return back to the capillaries while the remaining 15% return to the blood circulation through the lymphatic vessels
Lymphatic organs and tissues are sites of lymphocyte maturation.
The Lymph lymphatic vessels pass through lymph nodes which filtrate the lymph and add lymphocytes
(B. lymphocytes & T. lymphocytes).
lymph (lymphatic fluid) = plasma – blood cells
lymph (lymphatic fluid) = plasma+ lymphocytes
lymph nodes scattered all over the body they contain B. lymphocytes T. lymphocytes macrophage
lymphatic capillary
lymphatic trunks
lymphatic collecting vessels
lymphatic ducts
Lymphatic vessels
lymphatic vessels begin from the spaces between the cells and end into the venous system (blood circulation)
lymphatic vessels like veins has valves
collect into two main trunks thoracic duct right lymphatic duct
Function of lymphatic system
absorption of fat immunity maintain blood volume