Circulatory System Flashcards
What does the circulatory system consist of
Cardiovascular and lymphatic system
What are the functions of the circulatory system
Delivers gases, nutrients and hormones to the cells and tissues aswell as removing waste products
What is the cardiovascular system made up of
Heart, blood, circuit of blood vessels
Where is the heart located
In the thorax between the lungs and is protected by ribs
Atrioventricular valves
Connect the atria with the ventricles and prevent back flow of blood from the ventricle to the atrium
Semilunar valves
Guard the entrance to the pulmonary trunk aorta and prevent backflow of blood into ventricles
Where does the superior vena cava and inferior vena cava open into
Right atrium
Where does pulmonary trunk exit from
Exits from right ventricle and forms right and left pulmonary arteries
(Going to lungs)
Where do the pulmonary veins empty into
Left atrium
Bringing blood rich in oxygen
Where does the aorta exit from
Left ventricle
Takes blood around body
Blood flow through the heart
- blood low in oxygen returns to heart in the SVC and ICV and drains into the right atrium
-passes through tricuspid valve into right ventricle
-passes through pulmonary valve into pulmonary trunk and pulmonary arteries for delivery to lungs
-blood rich in oxygen returns from lungs to the heart in the pulmonary veins and drains into left atrium
-passes through bicuspid valve into left ventricle
-passe through aortic valve into the aorta for delivery around the body
What supplies the heart muscle
Right and left coronary arteries arise from aorta and supplies the heart muscle
How much blood does the heart muscle receive
5% of circulating blood
Why does the heart require a good blood supply
It contracts approximately 75x per minute
What is blood involved in
Respiration, nutrition, elimination of waste, immune defence, water and acid base balance
Components of blood
Plasma, formed elements, red blood cells, white blood cells and platelets
What is plasma and what does it contain
Clear fluid which contains plasma proteins, enzymes, nutrients, wastes, electrolytes, hormones, gases
What do red blood cells do (erythrocytes)
Delivers oxygen from the lungs to the tissues and transports carbon dioxide from the tissues to the lungs
What are the 3 adaptations of erythrocytes
Biconcave discs - increased surface area
Lack nuclei- unable to repair- live for approximately 120 days
Lack mitochondria- cannot use the oxygen
How much haemoglobin do red blood cells have
280 million molecules of haemoglobin in each red blood cell which binds to oxygen
White blood cells (leukocytes) function
Provide defence against invading pathogens
What are the 5 kinds of white blood cells
- neutrophil
- eosinophil
- basophil
- monocyte
- lymphocyte
Neutrophil
Phagocytose bacteria
Increase during bacterial infections
Eosinophil
Phagocytose antigen, antibody complexes and allergens
Destroy parasites
Increase during asthma, allergies and parastitic infections
Basophil
Secrete histamine and heparin
Increase with chicken pox, sinusitis, diabetes mellitus, myxdema
Monocyte
Differentiate into tissue macrophages to phagocytose debris and bacteria. Increase during viral infection and inflammation
Lymphocyte
Involved in immune response, may secrete antibodies
Increase during infections and immune responses
Platelets (thrombocytes)
- involved in clotting
-secrete vasoconstrictions - form platelet plugs
-dissolve old blood clots
Blood vessels
-series of vessels that compete a full circuit
Artery > artériole>capillary>capillary>venule>vein
Arteries
Subject to high pressure
Thick walls
Thick tunica media
Maintains shape
Veins
Low pressure system
Thin walls
Easily distensible
Contains valves
Capillaries
- site of gaseous, nutrient and waste exchange
-thin walled, endothelial layer and basement membrane
Types of capillaries
Continuous, fenestrated (little gaps for larger molecules) and sinusoids (even more gaps)
Systemic circulation
- delivers blood rich in oxygen from left side of the heart to mostly body tissues
- returns blood in low oxygen to the right side of the heart
- high pressure system
-forms an extensive network of
Pulmonary circulation
-delivers blood low in oxygen from the right side of the heart to the lungs
-returns blood rich in oxygen to the left side of the heart
- low pressure systen
Brachiocephalic trunk
Arm, head and neck
Right common carotid artery
Head
Right subclavin
Limbs
Internal carotid
Brain
Right vertebral
Back of brain
What does the lymphatic system consist of
Network of lymph vessels
Lymph
Lymphatic tissues
Organs
Functions of the lymphatic system
Involved in the bodies defence mechanisms, provides a mechanism for the drainage of interstitial fluid
Role of the lymphatic system in circulation
- Fluid moves from the arterial end of the capillary into the interstitial space.
- Fluid moves from the interstitial space back into the capillary at the venous end.
- But approximately 15% is left behind.
- In the capillary the fluid is termed plasma, in the interstitial space it is called interstitial fluid.
- The excess fluid enters the lymphatic system and is retuned to the blood through lymphatic capillaries.
Lymphatic capillaries
- Once the fluid is here it is called lymph
- Blind ended tubes located adjacent to capillary beds.
- Lymph enters capillary and drains in the the lymph vessel.
Odema
When fluid remains in the tissues
Order of the lymphatic system
Lymph capillaries
Lymph vessels
Lymph nodes
Lymph trunks
Thoracic duct or right lymphatic duct
Right lymphatic duct
Right side of head and thorax and right upper limb
Right venous angle (junction of right internal jugular vein and right subclavain vein)
Thoracic duct
Remainer of body
Left venous angle (junction of left internal jugular vein and left subclavain vein)
