the cardiovascular system n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
The Cardiovascular System PowerPoint Presentation
Download Presentation
The Cardiovascular System

Loading in 2 Seconds...

play fullscreen
1 / 26

The Cardiovascular System - PowerPoint PPT Presentation


  • 193 Views
  • Uploaded on

November 2012. The Cardiovascular System. Dr. Mona Soliman, MBBS, MSc, PhD Department of Physiology College of Medicine KSU. Structure of the Heart. Structure of the Heart. The Atria Thin walled Receives blood from: the systemic circulation (right atrium)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Cardiovascular System' - mircea


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
the cardiovascular system

November 2012

The Cardiovascular System

Dr. Mona Soliman, MBBS, MSc, PhD

Department of Physiology

College of Medicine

KSU

slide3

Structure of the Heart

The Atria

  • Thin walled
  • Receives blood from:
    • the systemic circulation (right atrium)
    • the pulmonary circulation (left atrium)
  • Open into the ventricles via the:

Atrioventricular valves

(AV valves)

structure of the heart1
Structure of the Heart

The Ventricles

  • Thick muscular walled (why?)
  • Pump blood into:
    • Pulmonary trunk (right ventricle)
    • Aorta (left ventricle)
  • A fibrous tissue ring separate the atria from the ventricles (importance: electrical activity, AV valve)
the valves of the heart the atrioventricular valves
The Valves of the HeartThe Atrioventricular Valves
  • The Tricuspid Valve… between the right atrium and the right ventricle, 3 cusps
  • The Mitral Valve (bicuspid valve) … between the left atrium and the left ventricle, 2 cusps
the valves of the heart the atrioventricular valves1
The Valves of the HeartThe Atrioventricular Valves
  • Prevent back flow of blood from the ventricles to the atria
  • Held by chordae tendineae to papillary muscle
  • Contraction of papillary muscle…
the valves of the heart the semilunar valves
The Valves of the HeartThe Semilunar Valves
  • Located at the origin of the pulmonary artery and aorta
  • Open during ventricular contraction…why?
  • Close during ventricular relaxation…why?
  • The Aortic Valve
  • The Pulmonary Valve
cardiac muscle cell2
Cardiac Muscle cell
  • Striated
  • Contain actin and myocin filaments arranged in sarcomeres…contract by sliding mechanism
  • Branch and interconnect
cardiac muscle cell3
Cardiac Muscle cell
  • Gap junctions
    • Trans-membrane channel proteins, connecting the cytoplasm of the cells
    • Allow spreading of the action potential from one fiber to another
    • Allow cardiac muscle to function as a syncytium“all or none law”: stimulation of a single muscle fiber results in contraction of all the muscle fibers
    • Intercalated discs
electrical activity of the heart1
Electrical Activity of the Heart
  • Automaticity: capable of originating action potential
myocardial action potential
Myocardial action potential
  • Resting membrane potential in myocardial cells -90 mV

Stimulation of myocardial cell

Myocardial action potential

conduction of impulses
Conduction of Impulses
  • The sinoatrial node (SA node):
    • Located in the right atrium
    • Pacemaker of the heart
    • Is capable of originating action potentials
    • Highest frequency
  • The atrioventricular (AV) node

Located at the junction of the atria and the ventricles

    • Delay in the conduction of impulses so the atrium can contract before the ventricle
conduction of impulses1
Conduction of Impulses
  • The atrioventricular (AV) bundle (Bundle of His)
  • The right and left bundle branches
  • Purkinje fibers
    • Spread within the muscle of the ventricular walls
    • Highest speed of conduction
contractility
Contractility
  • Contractility is the ability of cardiac muscle to convert chemical energy into mechanical work
contractility1
Contractility

Depolarization of myocardial cell

Opening of Ca2+ channels

Ca2+ increase in the cytoplasm

Ca2+ binds to troponin

Contraction

slide25

Contractility

Repolarization of myocardial cell

Ca2+ OUT

Ca2+ decrease in the cytoplasm

Relaxation

contractility2
Contractility
  • Absolute refractory period
    • Cardiac muscle cannot be excited while it is contracting
    • Long ARP
    • Time: depolarization & 2/3 of repolarization
  • Relative refractory period
    • Time: last 1/3 repolarization
    • Strong stimulus can give rise to contraction