The Circulatory System
watch video
Functions of the circulatory system
■ Transports oxygen, nutrients, and hormones to cells
throughout the body
■ can you name some nutrients?
■ can you name some hormones?
■ Transports metabolic wastes (carbon dioxide / urea)
from body cells for excretion (in lungs / kidneys)
■ Aids in homeostasis (ex. temp, pH, blood sugar)
■ Aids in defending body against disease (immune cell
/ antibody transport) & healing wounds (blood
clotting)
Movement
of the blood
through the
body
passes through
two circuits:
- pulmonary
circuit (lungs)
- &
- systemic
circuit (body)
Oxygenated vs
deoxygenated
blood
●
●
●
deoxygenated blood
from body returns to
right atrium
pumped to right
ventricle, then out to
lungs where blood is
oxygenated
oxygenated blood
returns to left
atrium, then to left
ventricle which
pumps it out to body
the heart
interactive:
Label the heart
Mitral or
Bicuspid
Valve
watch: The Amoeba
Sisters: Circulatory
System and Pathway of
Blood Through the Heart
(take some notes!)
what do heart valves actually look like?
Phases of the heartbeat
Systole = contraction
Diastole = relaxation
Ventricular Systole – both
ventricles contract
Ventricular
What is happening to atria during
ventricular systole?
Ventricular Diastole - both
ventricles relax
What is happening to atria during
ventricular diastole?
Ventricular
blood
vessels
function & structure / cross sections of blood vessels
Arteries:
- function: carry blood away from heart (to lungs or to body)
- structure: thick, elastic muscular walls and small lumen (opening) to
withstand and maintain high pressure from ventricles
Capillaries:
- function: exchange of O2/CO2 and nutrients/wastes within tissues
- structure: extensively branched throughout all tissue to reach all cells; very
small; walls only one cell thick for exchange of gases, nutrients and wastes
Veins:
- function: carry blood towards heart (from lungs or body)
- structure: thinner walls and larger lumen; also have valves to prevent
backflow due to loss of pressure when blood passes through capillaries
Velocity and pressure of blood in blood vessels
Blood pressure
measures force of the blood on
the walls of the blood vessels
during ventricular systole and
ventricular diastole.
Blood pressure video link
Blood pressure in capillaries
drops due to vessels being so
branched out (which increases
surface area for nutrient and
waste exchange), so veins need
help getting blood back to heart.
Veins have valves which help
prevent backflow, but veins
are also embedded in muscles
Contraction of these muscles
helps blood flow back to heart.
How might exercise help
improve circulation?
Varicose veins
result from faulty valves
in veins that cause blood
to backflow and pool
High blood pressure
High blood pressure, or hypertension, can place strain on walls of
arteries; may cause artery to burst.
Risk factors include being overweight; unhealthy diet (inc. salt, fat,
cholesterol); stress; family history (genetics); diabetes; etc.
Can be worsened by plaques which
are caused by inflammation in blood
vessels and the buildup of fatty and
mineral deposits (called
atherosclerosis) which can decrease
lumen and increase pressure
How blood pressure works video
Blood Pressure and Heart Rate Lab
test your fitness!
Blood components
plasma - mostly water; liquid part of blood
● red blood cells (erythrocytes) - carry O & CO
2
2
● white blood cells (leukocytes) - defense
against disease
● platelets (thrombocytes) - help in blood clotting
● solutes - proteins, salts, nutrients, wastes
●
Separation of blood components
Blood tests (source NHS):
Overview
Examples
Platelets are cell
fragments that help
Thrombocytes (platelets)
in formation of blood
clots.
work together with
fibrin protein to
close broken blood
vessels.
HW: GIZMOS: Circulatory System
Physiology Design Lab
Aim:
To design an experiment to see how some factor (IV) affects a
physiological condition or response (DV)
i.e. How does X affect Y?
You will gather data, using your friends (in class or outside of class) and
members of your family (if they are willing).
Data collection should happen during class time and include as many
trials as you can do during this time period (about 2h of data collection
will be expected)
This is a full lab write-up due through Turnitin on Wed, 2/Apr
Ideas to explore (as IV or DV):
-
breathing rate (bpm)
heart rate (pulse)
blood pressure
strength
exercise intensity (using timer or sports
apps)
- warm up time
- recovery time
- flexibility
- balance
- reflex / response time (see link next slide)
- short term memory (see link next slide)
- relaxation techniques
- temperature
- sweat and cooling
- time of day
- sleep cycles
- age/sex
can you think of other themes?
Human Benchmark (various tests)
short term memory test 1
short term memory test 2
reaction time test 1
reaction time test 2
other brain game links