Please enable JavaScript.
Coggle requires JavaScript to display documents.
27/2 Comparative anatomy -Cardiovascular System (Blood Vessels (Arteries…
27/2 Comparative anatomy
-Cardiovascular System
Circulatory System
Function
Transportation
Respiratory
Nutrritive
Excretory
Regulation
Hormone transport
Temperature regulation
Protection
Blood clotting
Immune defence
Heart
Composed of 3 layers
Pericardium (epicardium)
Myocardium
Endocardium
Mammalian Heart
4 distinct chambers
Right atrium
Right ventricle
Left atrium
Left ventricle
2 pairs of valves
Atrioventricular (AV) valves
Tricuspid valve-right AV valve
Bicuspid valve-left AV valve
Semilunar (pocket) valves
Pulmonary valve
Aortic valve
Circulatory route
Blood returns to the heart from vena cava into the right atrium
Passes into the right ventricle, then to the lungs through the pulmonary artery
Oxygenated blood returns through the pulmonary vein to the heart.
Leaves heart under pressure through the dorsal aorta (main artery of the body)
..
Coronary arteries-
-Supply heart muscle with blood
-Smaller arteries that run over the surface of the heart
Heart does not use blood contained in its chambers.
Blood Vessels
Arteries and arterioles
Carry blood away from heart
Branching system of blood vessels
that deliver blood to capillary beds
Larger arteries
Smaller arteries
Capillaries
Carry blood through tissues
Venules
Veins and veules
Same layer as arteries but thinner smooth muscle layer
2 major veins
-Superior vena cave
-Inferior vena cava
Lymphatic System
Functions
Drain away excess tissue fluid and return it to the blood
To absorb and transport fats
To filter our bacteria and toxins in lymph nodes
To return proteins to circulation
..
Tissue fluid
-Plasma
-Bathes all cells
Lymph
Plasma minus nutrients, oxygen and waste products and WBC
Closed system
Fluid enters through walls
Thoracic duct
Lymph nodes
The spleen
Large lymphatic organ
Important reservoir of red blood cells
The Cardiac Cycle
Contraction & Relaxation
Systole
Dustole
Two stages
1st stage
Blood enters left and right atria at same time time
2nd satge
When ventricles full, valves close,
AV valve
Fibrous ring acts as insulator between atria and ventricle syncytium
Electrical conduction
Sinoatrial node (SA) in right atria-generate their own electrical impulse =pacemaker-produces heart beat.
Depolarisation of SA node spreads through gap junction across atria
Reaches Atrioventricular node- dalays- allows atria to finish contracting before ventricles start
Signal moves from AV node to Bundle of His though ventricles and finally to Purkinje fibers
Purkinje fibers transmit to apes of heart and papillary muscle
...
Heart Rhythm
Small animal have higher heart rate
Heart rate (BPM)
-Refers to cycle of heart
Cardiac output
Stroke volume
-Volume of blood leaving left ventricle with each beat
Why important to know
Decreased cardiac output is the hallmark mechanism for shock
Heart rate
-Number if beats per minutes
CO=SV x HR
(mL/min) (mL/beat) (beats/min)
Auscultation
Lub= Av valves closing
Dup= Semilunar valves closing
Electrocardiogram (ECG)
Electrical activity of heart can be monitored from outside the body
Regulating Circulatory System
Respond to body demands by
Increasing heart rate
Increase blood pressure
Directing blood to specific organs
Neural control
Hormones