Transcript Cardiovascular Physiology - Mr. Bell`s Anatomy and Physiology

Types of Blood Vessels
ARTERIES
Arterioles
capillaries
Venules
VEINS
Structure of Blood Vessels
• Tunica Intima: thin
innermost layer of
endothelium
• Tunica Media: middle
layer of smooth muscle;
thickest layer
• Tunica Externa:
outermost layer; fibrous
Structure of Blood Vessels
• Capillaries
– Only have tunica intima to easily let things in and
out
• What passes into and out of the capillaries??
– CO2/O2, nutrients/waste
Trace Pathway Through Heart As
Class
• Right Atrium
• Right Atrium
Animation of Blood Flow
• http://www.biologyinmotion.com/cardio/cvsy
stem.swf
Blood Flowing Through the Heart
Re-Label ALL parts (including valves)
Refresh your memory…
• In order to push blood OUT of the heart what
part(s) of the heart contract(s)?
– ventricles
• Do the contractions occur simultaneously or
at separate times?
– simultaneously
Vocab Differences
• Atrioventricular (AV) valves = tricupsid &
mitral (bicupsid) valves
• Semilunar (SV) valves= pulmonary & aortic
valves
Heart Sounds
• Heart beat sounds like Lub dup
– Lub
• AV valves close after atrial systole
– Dup
• Closing of semilunar valves after ventricular systole
– Pause
• Refilling of chambers
Cardiac Cycle (heart beat)
= alternate periods of:
 Diastole: muscle relaxed; chambers filling; blood
flowing passively
 Systole: muscle contract; chambers empty; signal
for blood to move in appropriate direction
What makes gas exchange in the
capillaries?
• Pressure
• Things move from a __________ pressure to
___________ pressure.
Pressure Presence
• Pressure within heart chambers will cause
valves to open & close like a door opening &
closing
CARDIAC CYCLE
4 Step Process to Lub/Dub
4 steps to Cardiac Cycle
1.
2.
3.
4.
Atrial Diastole
Atrial Systole
Ventricular Systole
Ventricular Diastole
1. Atrial Diastole
•
•
•
•
Atria RELAXED
SV valves= CLOSED
AV valves= OPEN
Blood flow from veins
INTO heart (atria)
2. Atrial Systole
•
•
•
•
Atria CONTRACT
SV valves= CLOSED
AV vales= OPEN
Blood moves into
ventricle
3. Ventricular Systole
• Ventricle CONTRACT
• AV valves = CLOSE (LUB)
• Because AV valves close…
– Volume decreased
– Pressure increase
• Causes SV valves to OPEN.
Blood flow into artery
4. Ventricular Diastole
• Ventricle RELAX
• SV valves CLOSE (DUP)
• AV valves OPEN
• Restart process
Atrial Diastole
Atrial Systole
Ventricular
Systole
Ventricular
Diastole
Contract/Relax
Relax
Contract
Contract
Relax
AV valve
(open/close)
open
open
close
Open
SV valve
(open/close)
close
close
open
Close
Blood flow to…
Into atria
Into ventricle
Into artery
Capillaries, to
veins
The Cardiac Cycle
http://bcs.whfreeman.com/thelifewire/conte
nt/chp49/49020.html
ON A PIECE OF PAPER…
• Place the following events of the cardiac
cycle in order & then put the #s of what
occurs at each
A. Atrial Diastole
B. Ventricular systole
C. Atrial systole
D. Ventricular diastole
1.
2.
3.
4.
5.
6.
SV valves close
SV valves open
AV valves close
AV valves open
Dup
Lub
• What purpose
do the valves
serve?
Cardiac Cycle & Heart Sounds
1) Atrial Diastole: blood flowing into atria
2) Atrial Systole: blood flowing into ventricles
3) Ventricular systole: ventricles contract, atria
diastole/relax
1) AV valves close: prevent backflow (Lub)
4) Ventricular diastole: atria filling, ventricles
relaxing
1) SV valves close: prevent backflow (Dup)
Animations
• http://library.med.utah.edu/kw/pharm/hyper
_heart1.html
• http://msjensen.cehd.umn.edu/1135/links/An
imations/Flash/0028-swf_the_cardiac_cy.swf
• http://www.azisoft.com/Cardiovascular_Syste
m.swf
Controlling the heart
• Nodal System
– The Pacemaker
– Special tissue that is a cross between muscle and
nervous tissue that controls heart contractions
• Three parts:
1. Sinoatrial node
2. Atrioventricular node
3. Atrioventricular bundles
Nodal System
• Sinoatrial Node
– Located in the right
atrium
– starts each heart beat
• Atrioventricular Node
– Located at junction
between atria and
ventricles
Nodal System
• Atrioventricular Bundles
– Branch off from the AV
node and trigger
ventricular contraction
SA Node starts
impulse
AV Node triggered
Atria
Contract
PAUSE
Impulse travels through AV
Bundlesbundles
Ventricles
Contract
Cardiac Cycle
During what phase do the AV valves close?
- Ventricular Systole
During what phase do the SV valves open?
-Ventricular Diastole
During what phase do the SV valves close?
-Ventricular Diastole
Where are the SA & AV nodes?
Combining Cardiac Cycle & Nodes
Place these events in order during a heart beat:
1. Atria fill with blood
2. SV valves close
3. AV valves close
4. SA node receives signal
5. Atrioventricular Bundles receive impulse
6. Ventricles contract (systole)
Correct Order
• 4, 1, 5, 6, 3, 2
ECG Video
• http://www.youtube.com/watch?v=nK0_28q6
WoM
Electrocardiogram (ECG)
• Recording of electrical changes that occur in
heart tissue during one heart beat (or cardiac
cycle)
• Electrodes are placed on skin & wires are
connected to a machine
that responds to weak
electrical changes.
ECG Pattern
• Several waves
– P wave: depolarize atria by SA node
– QRS complex: depolarization of ventricle by AV
node to AV bundles (larger electrical change b/c
ventricular walls are thicker than atria)
• Atria repolarizing at same time
– T wave: after contraction of ventricle,
repolarization of ventricles
Label what happens at each wave
Animation: Cardiac Cycle w/ ECG
• http://library.med.utah.edu/kw/pharm/hyper
_heart1.html
Heart Rate
• Controlled by SA node
– Impulses sent from medulla oblongata which
receives sensory impulses & relays motor impulse
back to the heart.
– Impulses from cerebrum or hypothalamus can
influence rate
• Decrease heart rate after you faint
• Increase heart rate b/c of anxiety
Heart Rate
• Also affected by temperature & ions
– High body temperature (fever) increased rate
– Low body temperature decreased rate
– K+ & Ca++ if too much or too little
Circulation Physiology
• Vital Signs
– Pulse
– Blood Pressure
Pulse
• Expansion and contraction of arteries
• Pressure Points (aka pulse points)
– Locations on the body where the arteries are close
to the surface and are easily felt
Pressure Points
Acupuncture
• Eastern medicine– not western medically
proven to work.
– Needles in pressure points to find chi/balance of
body’s force
Blood Pressure
• Pressure blood exerts on the walls of blood
vessels
Blood Pressure Gradient
Blood Vessel
Pressure
Aorta
Arterioles
Systolic: 120
Diastolic: 90
Systolic: 110
Diastolic: 80
65
Capillaries
15
Venules
5
Veins
1
Venae Cavae
0
Arteries
Factors Affecting Blood Pressure
• Neural Factors
– Nerves can cause blood vessels to constrict
• Renal Factors (Kidneys)
– Changes the amount of water in blood which
changes blood volume which changes pressure
• Temperature
– Coldness causes blood vessels to constrict
– Heat causes them to dilate
Factors Affecting Blood Pressure
• Chemicals
– Drugs (including alcohol) alter heart rate and can
cause blood vessels to dilate or constrict
• Diet
– Salts, saturated fats, and cholesterol can lead to
high blood pressure
Blood Pressure
• Hypotension
– Low blood pressure (< 100 mmHg)
– Most commonly caused by blood loss
• Hypertension
– High blood pressure (> 140/90)
– Long-term effects: strains heart and damages
blood vessels
• http://www.youtube.com/watch?v=HNuPWdfj
Doc (how veins work)
• http://www.youtube.com/watch?v=Nb4jppGGUs&feature=fvst (blood pressure)
• http://www.youtube.com/watch?v=tAmLbclS
ucQ (high blood pressure)
• http://www.youtube.com/watch?v=02tpzvme
N_I (new method to lower bp)
BP Article
• http://www.nhlbi.nih.gov/health/dci/Diseases
/Hbp/HBP_WhatIs.html
How does one measure the strength of
a heart?
Cardiac Output
• Cardiac Output (CO)
– Amount of blood pumped out by each side of the
heart in 1 minute (ml/min)
• Stroke Volume (SV)
– Volume of blood pumped out by a ventricle with
each heart beat (ml/beat)
• Heart Rate (HR)
– Number of beats per minute (bpm)
Cardiac Output
• Equation
• CO = HR x SV
• Example: Average heart rate is 70 bpm and
the average stroke volume is 70 ml/beat.
What is the average cardiac output?
• If a person has a larger heart, how would this
affect his/her cardiac output?
To increase cardiac output…
• Increase heart rate
– When might your body do this?
• Increase stroke volume
– How might your body do this?
Composition of Blood
I. Functions
1. Transports nutrients, oxygen, wastes,
hormones
2. Maintains stability of fluid between tissues
3. Distributes heat
What is blood made of?
1. Solid (formed elements) 55%
A. Red blood cells
B. White blood cells
C. Platelets
2. Liquids 45%
D. Plasma
A. Red Blood Cells
aka erythrocytes
• Shape: biconcave disc (like a lifesaver or
donut)
• How the shape helps the RBC to function:
– Increase surface area through which gases diffuse
Sickle-cell Anemia
• Mutation causes hemoglobin to crystalize
when O2 is not present
• Bends the RBCs into sickle shape
• Blocks circulation in small blood vessels
• Results in joint pain, organ damage
• FYI: 1 copy of mutation immunity from
malaria; 2 copies of mutation  sickle cell
disease
B. White Blood Cells
aka leukocytes
• Five types
• Function: protect against disease
– Produce proteins (antibodies) that destroy foreign
particles.
– Phagocytize (eat) bacterial cells.
C. Platelets
• Aka thrombocytes
• Structure:
– Not complete cells
– Come from large cells in bone marrow that
fragment
• Function:
– Controls blood loss from broken blood vessels
– Initaite blood clots
D. Plasma
• Water, amino acids, proteins, carbohydrates,
lipids, vitamins, hormones, electrolytes,
cellular waste.