Transcript 37.1 The Circulatory System

Anatomy and Physiology of the
Circulatory System and Blood
I. Function of blood and circulatory
system
a.
b.
c.
Distribute heat, food, and oxygen.
Removal of waste.
Regulation of H2O content.
II. Components of Blood
a.
Cellular
Erythrocytes (RBCs)
2. Leukocytes (WBCs)
3. Thrombocytes (Platelets)
Erythro = red
Leuko = white
Cyte = cell
Thrombo = clot
1.
b.
Non-cellular
4.
Plasma
 Connected
to our blood (vascular) system is
the lymphatic system, a one-way system
that returns excess fluid from tissues to the
blood stream – also helps fight infections.
Blood Volume:
58% plasma, 42% blood cells (primarily
RBCs)
 Body volume = 5-6 liters; 9-12 pints (8% of
body weight)
 Blood is sticky, thick (5 times as thick as
water), salty taste, and ph=7.4

III. Origin of Blood Cells A.
B.
As a child: all bones produce blood cells.
As an adult only: humerus, femur,
sternum, ribs, scapula, clavicle, vertebrae,
ilia, and cranium.
IV. Erythrocytes/RBCs
No nucleus
 Life span = 120 days
 Small disc shape
 Carries O2
 Surface is elastic so they can squeeze
through capillaries.

V. Leukocytes/WBCs
Nucleus
 Fights infection
 Phagocytes – surround & engulf bacteria &
viruses.
 CBC = complete blood count
 Elevated WBC count = infection

VI. Plasma
92% H2O + salts (Na+, K+, Mg+, Cl-)
 Proteins (fibrogenin, hormones, enzymes,
vitamins…)
 After a meal - ↑ nutrients in the plasma
 After exercise - ↑ in wastes in the plasma

VII. Platelets
Small, no nucleus, irregular shape.
 Initiate a blood clotting chain of reactions.

VIII. Blood
Clotting/Coagulation/Homeostasis
Small vessels constrict
 Platelets stick to surface of wound until plug
is formed.

IX. Blood Types

Discovered by Karl Land Stemer – 1900
A.
Genetics
3 Genes: A, B, O
AA + AO  A
BB + BO  B
AB  AB
OO  O
X. Importance of Blood Typing
1.
2.
3.
Blood transfusions – if wrong, tiny blood
clots throughout the body.
Legal-paternity cases – determine who
parents can or can’t be (father)
Rh factor –




A blood protein
Rh+ - 85%
Rh- - 15%
- important to know in pregnancy.
The Heart
Heart Structure
I.



Hollow muscular organ; sits about 2/3 to the
left of the midsagittal plane.
Have a set number of cells at birth – only ↑ in
size of cells.
Enclosed in a pericardial sac (pericardium) –
actually 2 membranes – outer parietal and
inner visceral – between the two is
pericardial fluid which prevents friction due to
heartbeats.


Muscle wall = myocardium – striated,
involuntary cells
4 chambers
1.
2.
3.
4.

Top = atria – receiving chambers
Bottom = ventricles – pumping chambers
Right side = pulminary circulation
Left side = systemic circulation
Right side receives deoxygenated blood
and pumps to the lungs then to the left
side of the heart out to the body.
II. Heart Valves




Right Atria
Tricuspid
valve
Right Ventricle
Left Atria
Semilunar
valve
Bicuspid
valve
Left Ventricle
Right Ventricle
Left Ventricle
Semilunar
valve
Pulmonary Artery
Aorta
* Bicuspid valve is
much stronger than
the tricuspid because
the left ventricle
exerts a greater force
than the right.
III. Blood Supply to the Heart
Since the heart is a muscle, it also needs
blood, oxygen and nutrients.
 Coronary arteries supply myocardium with
blood.
 If coronary artery is blocked…must bypass
blockage.

IV. Heart Conducting System
1.
Specialized heart muscle cells in right
atrium that set the pace of the heartbeat =
pacemaker or SA node
V.
1.
2.
3.
Control of the Heart
Hormones – thyroid, adrenal (increases
heart rate) brought on by stress and fear.
Nervous System – variety of receptors
cause nerves to release a variety of
chemicals.
Chemical Influence


Atropine – nightshade plant that increases
heart rate greatly.
Muscarine – poisonous mushroom - stops
heart entirely.
PHOTOS
Nightshade Plant
containing atropine
Poisonous Mushroom
containing muscarine
VI. Factors Affecting Heart Rate
1.
2.
3.
Age – pre-birth 140-160 then declines until
age 20 when it is constant at 70-75/min.
Sex – women slightly higher than men.
Physical Conditioning – athletes lower.
VII. Heart Sounds
A.
Lub – sound of ventricles contracting

B.
Best heard at approximately over the 5-6th rib
of left sternum.
Dub – sound of closing semilunar valves.


Sound is shorter in duration & higher pitch.
Best heard between 2nd and 3rd ribs near the
sternum.
VIII. Heart Disorders
1.
2.
3.
4.
5.
Ischemia – lack of blood to part of the
heart.
Fibrillation – heart irregularities.
Tachycardia – rapid heart beat.
Heart murmur – from faulty valves
Atrial or ventricular holes


mix O2 & CO2 blood.
Victim turns blue.