Download circulation

CIRCULATION
Types of circulatory systems
• Diffusion – oxygen and carbon dioxide, based on body
shape and size
• Gastrovascular cavities – distribution of substances
throughout the body and in digestion.
• Open circulatory system – arthropods, some molluscs
• Hemolymph, interstitial fluid, clear fluid
• Pumped through vessels into sinuses and back to heart
• Closed circulatory system –
• Blood confined in vessles
FIGURE 34.3
(a) An open circulatory system
(b) A closed circulatory system
Blood
Heart
Heart
Interstitial
fluid
Hemolymph in sinuses
Branch vessels
in each organ
Pores
Dorsal vessel
(main heart)
Tubular heart
Auxiliary
hearts
Ventral vessels
Cardiovascular system
• Closed circulatory system of humans
• Arteries – blood away from heart
• Capillaries – gas exchange, simple squamous tissue
• Veins – blood to the heart
• Not all arteries carry oxygenated blood and not all veins
carry deoxygenated blood
• 2 main chambers of the heart
• Atrium – receiving chamber
• Ventricle – pumping chamber
Figure 34.4
(a) Single circulation: fish
Gill capillaries
(b) Double circulation:
amphibian
Lung
and skin
capillaries
A
Right
Vein
Pulmonary
circuit
Pulmocutaneous
circuit
Artery
Heart:
Atrium (A)
Ventricle (V)
(c) Double circulation:
mammal
Lung
capillaries
A
V
A
Left
Right
V
A
V
Left
Systemic
capillaries
Body capillaries
Key
Oxygen-rich blood
Oxygen-poor blood
Systemic circuit
Systemic
capillaries
Systemic circuit
Figure 34.5
Superior
vena cava
Capillaries of
head and
forelimbs
7
Pulmonary
artery
Pulmonary artery
Capillaries
of left lung
Aorta
9
Capillaries
of right lung
6
2
3
3
4
11
Pulmonary
vein
Right atrium
1
Pulmonary
vein
Left atrium
5
10
Left ventricle
Right ventricle
Inferior vena cava
Aorta
8
Capillaries of
abdominal organs
and hind limbs
Figure 34.6
Aorta
Pulmonary artery
Pulmonary
artery
Right
atrium
Left
atrium
Semilunar
valve
Semilunar
valve
Atrioventricular
(AV) valve
Atrioventricular
(AV) valve
Right
ventricle
Left
ventricle
The mammalian heart
• Approximately the size of a fist
• Made of mostly cardiac tissue
• Cardiac cycle – one complete sequence of pumping and
filling of the heart.
• Systole – contraction phase of cardiac cycle
• Diastole – relaxation phase of cardiac cycle
• Cardiac output – volume of blood each ventricle pumps
per minute
Valves
• Atrioventricular – separate the atrium from the ventricle
• Bicuspid – mitral valve
• tricuspid
• Semilunar valves – found at exits of the heart
• Pulmonary – leaving heart for lungs
• Aortic – leaving the heart to the aorta
• Lub Dup
• Lub – blood against the closed AV valves
• Dup – closing of semilunar valves
• Murmurs – abnormal sounds
Conduction system
• sinoatrial node – pace maker – sets rate and timing of
cardiac muscle contraction.
• Atrioventricular node – conduct impulses through wall
separating atrium and ventricle
• ECG – electrocardiogram – graph depicting stages in the
cardiac cycle
Figure 34.8-4
1 Signals (yellow)
from SA node
spread
through atria.
SA node
(pacemaker)
ECG
2 Signals are
delayed
at AV node.
AV
node
3 Bundle
branches
pass signals
to heart apex.
Bundle
branches
Heart
apex
4 Signals
spread
throughout
ventricles.
Purkinje
fibers
Blood vessels
• 3 layers of tissue
• Endothelium – think epithelial tissue
• Smooth muscle
• Durable connective tissue
• Artery – arterioles – capillaries – venules - veins
• Arteries and veins differ slightly in structure
• Arteries have thicker walls due to higher pressure
• Veins have valves to prevent backflow
Figure 34.9
LM
Artery Vein
Red blood
cells
100 m
Valve
Basal lamina
Endothelium
Smooth
muscle
Connective
tissue
Endothelium
Smooth
muscle
Connective
tissue
Capillary
Artery
Vein
Capillary
15 m
Red blood cell
Venule
LM
Arteriole
Blood pressure
• Arterial blood pressure is highest during systole
(contraction)
• Pulse – rhythmic bulging of the artery walls with each
heart beat.
• Diastole – relaxation phase, arteries go back to normal,
lower pressure
Homeostasis
• To maintain blood pressure as best it can...
• Arterioles will dilate or constrict
• Endocrine and nervous system will produce Nitric oxide that will
induce vasodilation, regulating blood pressure
• Gravity – you will faint to get head level to heart, increasing blood
flow to brain
• Giraffes have higher systolic pressure, 250mmHg
• Lymphatic system – gains liters of fluid (lymph) a day
begin lost from capillaries.
• Lymph nodes – contain cells that destroy bacteria and viruses.
Figure 34.12
Blood
capillary
Interstitial
fluid
Adenoid
Tonsils
Lymphatic
vessels
Thymus
(immune
system)
Tissue cells
Lymphatic
vessel
Lymphatic
vessel
Spleen
Lymph
nodes
Appendix
(cecum)
Peyer’s patches
(small intestine)
Lymph node
Masses of
defensive
cells
Blood
• 55% plasma – liquid made of water, proteins, wastes, gas
• 45% - formed elements
• Erythrocytes – red blood cells
• Red biconcave disks
• No nucleus
• Formed in red bone marrow
• Leukocytes – white blood cells
• Immune system
• 5 types
• Thrombocytes – platelets
• Blood clotting
Figure 34.13
Cellular elements 45%
Plasma 55%
Constituent
Water
Ions (blood
electrolytes)
Sodium
Potassium
Calcium
Magnesium
Chloride
Bicarbonate
Major functions
Solvent for
carrying other
substances
Osmotic balance,
pH buffering,
and regulation
of membrane
permeability
Leukocytes (white blood cells)
per L (mm3)
of blood
Functions
5,000–10,000
Defense
and
immunity
Separated
blood
elements
Lymphocytes
Basophils
Eosinophils
Plasma proteins
Albumin
Number
Cell type
Neutrophils
Osmotic balance,
pH buffering
Fibrinogen
Clotting
Immunoglobulins
(antibodies)
Defense
Substances transported by blood
Nutrients (such as glucose, fatty
acids, vitamins)
Waste products of metabolism
Respiratory gases (O2 and CO2)
Hormones
Monocytes
Platelets
Erythrocytes (red blood cells)
250,000–400,000
5,000,000–
6,000,000
Blood
clotting
Transport
of O2 and
some CO2
Cardiovascular disease
• Disorders of heart and blood vessels
• Cholesterol
• Atherosclerosis – hardening of the arteries by fatty deposits
heart attack – myocardial infarction – damage or death of
cardiac muscle tissue resulting from a blockage of one or
more coronary arteries
Stroke – death of nervous tissue in the brain due to lack of
oxygen.
Hypertension – high blood pressure – damages
endothelium in arteries, promoting plaque build up