Cardiovascular Physiology.pdf by Dr kurawa FUD

A very fully informed and summarized slide on cardiovascular system

1. Cardiovascular
Physiology
Prepared
By
M.I. Kurawa

2. Muscle Tissue
•Muscle Tissue is another type of excitable tissue responsible for generating mechanical
force through contraction.
•Types:
•Skeletal Muscle: Skeletal muscles are attached to bones and are responsible for voluntary
movements. They contract in response to nerve signals and are under conscious control.
•Cardiac Muscle: Cardiac muscle is found in the walls of the heart. It contracts rhythmically
to pump blood throughout the body. Cardiac muscle has some similarities to skeletal
muscle but also possesses unique properties that allow for coordinated contraction and
the propagation of electrical signals, resulting in the heartbeat.
•Smooth Muscle: is found in the walls of various internal organs, such as the digestive tract,
blood vessels, and respiratory passages. It contracts involuntarily and is responsible for
processes like peristalsis (wave-like contractions) in the digestive system and regulating
blood vessel diameter.

3. Classifications
A)Based on striation
1. striated muscle
2. Nonstriated muscles
A)Based on control
A)Voluntary
B)Involuntary
B)Based on the function
A)Skeletal muscle
B)Cardiac muscle
C)Smooth muscle

6. 25µm in diameter

7. •Action potential reaching T-tubules open a
VGCa (dihydropyridine) channel. Small
amounts of Ca enters the cell & opens
Ryanodine channels which pour out Ca from
sarcoplasmic reticulum (SR).
•The process of excitation-contraction-coupling
as in skeletal muscles continue.
•Cardiac muscle has to quickly removes Ca2+
from cytoplasm to allow for the next
contraction through,
1.Na-Ca2+ exchanger
2.Ca2+ ATPase pumps Ca2+ out of the cell.
3.SR Ca2+ ATPase (SERCA)

8. •Duration of AP = 200 msec. in cardiac, 1 msec. in nerve & ≈2 msec. in skeletal muscles
•≈99% of the cardiac cells are fast-AP contractile myositis (which generates force), the
remaining are the slow-AP face-maker cells

9. Superimposed Twitch on Fast Action Potential in Relation to
Refractory Period

10. NB! In skeletal muscles more
& more fibers can be
recruited in order to develop
stronger & stronger
contractions. This is not the
case in cardiac muscle
because it act in unisom
(syncytium).
Frank sterling law: the more
the stretch of the
myocardium, the stronger
the contraction.

13. Btw the Rt & lt atrium the septum is made up of cardiac myocyte, therefore electrically coupled
Btw the atria & ventricles is separated by a connective tissue, therefore electrical activity from the atria only
pass to the ventricles through bundle of his

14. -35mV
-55mV

16. Resting HR= 60-80 bpm
Athletes tend to have
very low resting HR

17. Allows for complete evacuation of blood from atria

26. (Wigger’s Diagram)

27. B= end diastolic vol (EDV)
D= end systolic vol (ESV)

29. Athletes with lower HR have similar CO because with training the heart wall
becomes stronger and the chambers grow larger. This is because overtime the
heart has to meet the demands of the exercise. They compensate the lower HR
with a larger SV
CO = SV x HR
5000 ml/min = SV x 50
SV = 100 ml
Range of HR in an
Athlete: 50-200 bpm

32. In a normal heart, EF
is about 50-75%

39. Transition from elastic to
muscular arteries
Arteries = high pressure
system
Veins = low pressure & high
capacity

40. Slowest velocity is at
the level of capillaries.
This will allow time for
exchange of nutrients
and also waste with
the tissue cells

41. SBP
DBP

43. The distribution of blood to the
organs is based on demand. There is
no enough blood to perfuse all the
capillaries in all the organs at one
time
P2 & P1 = pressure gradients
Q organ= perfusion pressure for
that organ
After feeding, blood is diverted to GIT. During exercise, blood is diverted to
muscles. But, heart & Brain gets 100% perfusion at all times