HUBS192 - Cardiovascular System

Revision for L4, L5 & L6

Blood Vascular System

A closed supply and drainage system

~a continuous loop

Lymphatic (Vascular) System:

A open-entry drainage system

~ a one-way system

Supply side

• Arteries are the only supply path.

• Major arteries are situated to avoid damage (eg: deep in the trunk; on flexor aspect of limbs).

• Important structures often receive supply from two sources (two separate arteries).

• Arteries change their name at each major branch.

Exchange Network:

Capillaries of varying degrees of permeability

• Continuous (controlled ~ tight)

• Fenestrated (leaky)

• Sinusoidal (very leaky)

What kind of pump is the heart?

A pulsatile pump → It functions by rhythmically contracting and relaxing, propelling blood through the circulatory system in a pulsating manner

Two systems of the cardiovascular system:

• Blood vascular system (a continuous loop)

• Lymphatic System (a one-way system)

Arteries

Deliver Blood

Capillaries

Allow exchange

Veins

Return blood

What are the three components of the cardiovascular system?

Supply (arteries)

Exchange (capillaries)

Drainage (veins & lymphatics)

Shape of the heart?

Blunt & cone-shaped

3 Types of capillaries:

• Continuous (controlled ~ tight)

• Fenestrated (leaky)

• Sinusoidal (very leaky)

3 Pathways for drainage:

• Deep veins

• superficial veins

• Lymphatics

What is the pointed end of the heart?

The apex

What is the broad end of the heart?

The base

Whats the PMI?

The point of maximal impulse → where the loudest heart sounds will be heard, also where the apex beat can be observed 

The FOUR chambers of the heart:

• Right Atrium → receives deoxygenated blood from the body

• Right Ventricle → pumps blood to lungs via pulmonary artery

• Left Atrium → receives oxygenated blood from lungs via pulmonary veins

• Left Ventricles → pumps blood to the body via aorta (the largest artery in the human body)

Ventricles:

Pumping chambers (thicker walls)

→ left ventricle is thicker due to systematic resistance

Atria:

Receiving chambers (thin walls)

Three Layers of The Heart Wall:

• Endocardium

• Myocardium

• Epicardium

Endocardium layer:

Inner layer; squamous epithelium, connective tissue

Myocardium Layer:

Middle Layer; cardiac muscle

Epicardium Layer:

Outer Layer; connective tissue, adipose, blood vessels

What surrounds the entire heart organ?

The Pericardium → protective sack around the heart

Pericardium Layers:

• Fibrous pericardium → tough outer layer

• Serous pericardium → double layer

• Pericardial cavity → contains fluid to reduce friction

What makes up the heart wall (from outside in)?

• Pericardium

• Epicardium

• Myocardium

• Endocardium