Cardio-vascular system

Prof. Dr;Manal El-Sawaf

Cardio-vascular system

1. Heart2. Blood vessels

– Arteries– Veins– Capillaries

3. Lymphatic vessels

Blood vessels

• Arteries • Arterioles• Capillaries• venules• Veins

Arteries

definition:The vessels that

carry the blood away from the heart They carry oxygenated blood.

They have thicker walls than veins to withstand blood pressure.

The arteries have different sizes

Medium sized (deep) arteries are accompanied by venae comitantes.

• Smallest arteries are called arterioles

Anastomoses

• It is the joining of branches of arteries thus form a link between main arteries supplying an area.

• Arterial anastomoses provide alternative pathways called collateral circulation If one arterial branch is occluded

End arteries• Arteries that do not anastomose are

called anatomical end arteries, or which have a poor (not sufficient) anastomoses are called functional end arteries .

• when end artery is occluded as in (retina, kidneys, spleen & liver) the tissue it supplies dies.

                                             Note: the arterial wall is much thicker than the veins and arteries have no valves

Arteriovenous anastomosis

• Direct connection between the arteries and veins without the intervention of the capillaries

Veins

Veins carry blood towards the heartThey carry de-oxygenated blood

They have valves tostop the backflow of blood

Veins

• The smallest veins are called venules• Tributaries of veins that join each other areCalled venous plexuses

Arteries veinsCarry bl. From the heart To the heart

oxygenated De-oxygenated

Thick walls thin

Open Collapse when cut

No valves

Connection (anastomosis)

Valves

Connection(plexuses)

Capillaries• The smallest

arterioles break up to capillaries

• one endothelial layer forms the entire capillary wall

• the average diameter is 7 m

Sinusoids• Wider than

capillaries • Have thin walls• Sinusoids are

usually fenestrated

Sinusoids• Present in liver,

spleen, bone marrow and endocrine glands

Heart

Structure of the Heart

endocardium

myocardium

pericardium

pericardium

fibrous serous

visceral parietal

PericardiumFibrous pericardiumConical fibrous sac Attached to central tendon of

diaphragm inferiorly• Blends with outer coat of great

vessels superiorlySerous pericardium Visceral pericardium (epicardium)• Parietal pericardiumPericardial cavity• Potential space between visceral

and parietal pericardium • Contains film of pericardium fluid

PericardiumSerous pericardium:Serous sac invaginated by

the heart Has two layers:-Visceral pericardium• Parietal pericardium

Pericardial cavity• Potential space between

visceral and parietal pericardium

• Contains film of pericardium fluid

Heart external features

• Sulci 1.Coronary

sulcus(atrio-ventricular)

2.Anterior inter-ventricular

3.Posterior inter ventricular

Heart external features

• Borders 1.Superior: along it great vessels2. Right: formed byRight atrium3.Inferior: mainly by Right ventricle4. left: formed byLeft ventricle

Heart external features

l Surfaces :

Sternocostal(anterior)

Diaphragmatic(inferior)

Base(posterior)

Heart external features

• Surfaces :Sternocostal-right atrium-right ventricle -left ventricle

Heart external features

• Surfaces :Diaphragmatic(inferior)-right ventricle-left ventricle

Base(posterior):-left atrium

Surface markings of heart • lower border of lt 2nd

c.c1 ½ inches from mid-line

• To the upper border of right third costal cartilage 1 inch from the midline,

• To Rt sixth costal cartilage½ inch from midline

• To Apex － in the fifth left intercostal space 3 ½ from the midline in midclavicular line

• To the 1st point

Heart Valves -surface anatomy • Tricuspid valve

– Middle of sternum – at 4th intercostal space

• Bicuspid valve– Lt half of sternum at – 4th cc

• Aortic valve• Lt sternal margin at 3rd

• intercostal space

• Pulmonary valve– Sternal end of lt 3rd c.c

Pulmonary (3rdcc)Aortic(3rd space)

Mitral (4th cc)Tricuspid(at4th space)

Internal features

• Right &left• 4 chambers• Atrio-ventriculr

valves• Semilunar valves

Right atrium

• Features• openings

Right ventricle

• Inflowing• Outflowing• openings

Left atrium

Left ventricle

• Inflowing• Outflowing• openings

Blood supply of the heart

Circulation

• Pulmonary• Systemic• portal

Main vessels