Transcript The Cardio-vascular System

L3 Sport
Units 1 & 2: Anatomy & Physiology
Introduction
Identify key terms
associated with
the cardiovascular
system
Components of the Cardiovascular System
The main components of the cardiovascular
system are…
•
The Heart
•
Blood Vessels
•
Blood
The
Cardiovascular
System
TASK
Draw your own
diagram of the
CV system
The Heart
A specialised organ
consisting of four
chambers
‘double pump’
It works involuntary
through nervous
control
E
F
A
B
Right
Side
Left
Side
C
G
D
H
Aortic Valve
Opening of the Coronary Artery
Aorta
Opening of the Pulmonary Veins
Right Pulmonary Arteries
Superior Vena Cava
Left Pulmonary Arteries
Right Pulmonary Veins
Semi-Lunar Pulmonary Valve
Left Pulmonary Veins
Left Atrium
Right Atrium
Opening of the Coronary Vein
Mitral Valve
(Bicuspid Valve)
Tricuspid Valve
Entry of Aorta
Sino-atrial Node
Inferior Vena Cava
Left Ventricle
Right Venticle
Interventricular Septum
The Heart Wall
• Epicardium – is the
thin transparent
membrane
• Myocardium – is the
thick muscular wall
• Endocardium – is the
inner lining of the
Heart
The Heart & Blood Flow
• The right atria receives de-oxygenated blood
from the body
• The right ventricle pumps de-oxygenated
blood to the lungs
• The left atria receives oxygenated blood
from the lungs
• The left ventricle pumps oxygenated to the
body
Create a flow
diagram showing
the direction of
blood flow around
the cardiovascular
and circulatory
system
The Heart
TASK – Define the following key terms
associated with the heart and give ‘normal’
resting values for each (including units!)
Heart rate (HR)
Stroke Volume (SV)
Cardiac Output (Q)
Q = HR x SV
Blood Pressure
• Blood travels through the CV system under
pressure
• We can measure blood pressure using a
sphygmomanometer
• Normal resting value is 120/80 mmHg
• Systolic pressure – is the pressure exerted
by the blood during ventricular contraction
• Diastolic pressure – is the pressure exerted
by the blood during ventricular relaxation
• High / low bp?
Blood Vessels
Capillaries
Arteries
Veins
The Cardiovascular System
TASK – discuss and answer the following
1.
What do arteries do?
2. What do veins do?
3. Are there any differences between these
vessels?
4. What do oxygenated and de-oxygenated mean?
5. What is gas exchange and where does it
happen?
Blood Vessels
1.
2.
3.
4.
5.
Blood carrying vessels include:
Arteries
Arterioles
Veins
Venules
Capillaries
Q. What are the differences between these
vessels?
Arteries
• Arteries are large blood vessels that transport
blood away from the heart
• Arteries transport blood at high pressure, as a
consequence arteries need to be strong so they
have a thick muscular wall
• They have 3 layers – inner membrane, smooth
muscle, outer member
*Arteries usually carry
oxygenated blood… what is
the exception?
Arterioles
•
•
•
•
Arteries split into arterioles
Arterioles deliver blood to capillaries
They carry blood at a fairly high pressure
They have 3 layers – inner membrane, smooth
muscle, outer member
Veins
• Veins carry blood to the heart
• Veins carry blood at a low pressure therefore
their walls do not need as much muscle
• They have 3 layers – inner membrane, smooth
muscle, outer member
• They have valves to prevent backflow
Venules
• Capillaries join to form venules
• Venules join to form veins
• They have 3 layers – inner membrane, smooth
muscle, outer member
• They do not have valves
Capillaries
• Capillaries are the blood vessels that enter a
tissue
• Diffusion takes place between the blood and
body through the walls of the capillaries
• In order to allow this to happen capillaries
have very thin walls (approximately one cell
thick)
• GAS EXCHANGE
Blood Vessels
Artery
Vein
Capillary
Vasoconstriction / vasodilation?
ARTERIES
ARTERIOLES
3 Layers
Middle Layer
Thick & Elastic
3 Layers
Smaller than
Atreries, More
Smooth Muscle
No Valves
CAPILLARIES
VENULES
VEINS
1 Layer
3 Layers
Thin Muscular
Middle Layer
3 Layers
Thinner Middle
Layer
Thicker Outer
Layer
No Valves
No Valves
No Valves
Pocket Valves
High Pressure
High Pressure
Pressure
Changes
Low Pressure
Low Pressure
Carries Blood
Away From Heart
Controls Blood
Flow & Pressure
Gaseous
Exchange
Carries Blood
Towards Heart
Carries Blood
Towards Heart
Arteries
Structure
Pressure
Function
Image
Arterioles
Veins
Venules
Capillaries
Q. What are the roles of the
cardiovascular system???
Discuss and feedback your ideas
Functions of the CV System
1. Delivery
• Of oxygen and nutrients e.g. glucose
• To the tissues e.g. muscle, brain
• Explain how…
• Explain why…
• Problems e.g. anaemia
Functions of the CV System
2. Removal
• Of waste e.g. carbon dioxide, lactic acid
• Explain how…
• Explain why…
• Problems e.g. fatigue during exercise
Functions of the CV System
3. Thermoregulation
• Controlling body temperature
• Explain how… vasodilation / vasoconstriction
• Explain why…
• Problems e.g. heat exhaustion
Blood
• Plasma (approx 55%)
• Red blood cells (approx 45%)
• White blood cell
• Platelets
• Glucose, fat, proteins
Functions of Blood
1. Oxygen transport
• Describe the response
• Explain how… haemoglobin
• Explain why…
• Problems e.g. anaemia,
sickle cell anaemia
Functions of Blood
2. Blood Clotting
• Describe the response
• Explain how… platelets
• Explain why…
• Problems e.g. haemophilia
Functions of Blood
3. Fighting infection
• Describe the response
• Explain how… the immune system
• Explain why…
• Problems e.g. HIV virus
Q. What are the short and long
term responses of the
cardiovascular system to exercise?
Discuss and feedback your ideas
CV Responses to Exercise
Short-term:
• Anticipatory rise
• Increased heart rate and cardiac output
• Increased / redistribution of blood flow
•Increased blood pressure
• Thermoregulation
Q. Why do these changes occur?
Heart Rate
Heart
rate
Heart
rate
Exercise intensity
Exercise duration
Constant intensity
Stroke Volume
Constant intensity
Stroke
volume
Stroke
volume
Exercise intensity
Exercise duration
Increased venous return – increased stroke
volume – ‘Starling’s Law’
Regulation of HR - Venous Return
VENOUS RETURN is the volume of blood returning
to the heart, this is affected by:
MUSCLE PUMP
• contraction of skeletal muscle exerts pressure on
veins forcing blood to flow towards the heart
• backflow is prevented by pocket valves
RESPIRATORY PUMP
• during inspiration, pressure in thoracic cavity
decreases
• pressure in abdominal cavity increases
• blood moves up from compressed high pressure
(in abdomen) to low pressure (in thorax)
• during expiration, pocket valves prevent backflow
of blood into abdomen
Blood Flow
During exercise there is an increased
demand for O2 and nutrients by the muscles
to make ATP aerobically
Vasoconstriction and vasodilation redistribute
blood flow, increasing the amount going to
the muscles
‘blood shunting’
Thermoregulation
Q. What is thermoregulation?
Q. Why is it important?
Q. What changes are there during exercise and
why?
CV Responses to Short-term
Exercise
DEPENDS ON THE INTENSITY,
DURATION AND TYPE OF EXERCISE
YOU SHOULD ALSO CONSIDER THE
TRAINING STATUS OF THE
INDIVIDUAL!
The Long Term Effects of
Exercise on the CV System
•
•
•
•
•
•
•
•
•
Cardiac Hypertrophy – Increased wall thickness
Stroke Volume Increase
Cardiac Output Increase
Increased Capillarisation
Increased Haemoglobin
Increased Blood plasma volume
What are the
Decreased resting BP
consequences?
How do these
Quicker recovery
responses benefit
performance?
Better aerobic fitness