test 4 Flashcards
• Heart wall
Epicardium
• Myocardium
• endocardium
Cardiac Skeleton (4 functions?)
• Lies between the atria and ventricles – Anchors the valves – Prevents over-dilation – Point of attachment (fibrous ring) – Blocks electrical signals
fasciae adherens
binds the ends of cells to allow the force of one cell to be transmitted to adjacent ones
blood supply to the heart
left and right coronary arteries get blood from aortic canal, goes into coronary arteries, into capillaries, aortic veins, into coronary sinus and then right atrium
Coronary Artery Disease
=not getting enough oxygen to heart muscle
- angina: mild, presents chest pain
- Myocardial infraction(heart attack): complete arterial blockage, cells begin to die because of lack of oxygen
Heart Failure
=progressive weakening of the heart as it fails to keep up with blood pumping and oxygen demands
– Congestive heart failure: heart enlarges while pumping efficiency declines
– Pulmonary hypertension: enlargement and sometimes ultimate failure of right ventricle resulting from elevated BP in pulmonary circuit
Arrhythmia
=variation from normal heart beat
-fibrillation: rapid, random firing of ventricular muscle (ventricular fibrillation) or of the AV node (atrial fibrillation)
after centrifugation of blood sample
top: plasma (less dense, 55% of whole blood)
Middle: buffy coat (leukocytes and platelets, <1% of whole blood)
Bottom: erythrocytes (most dense, 45% of whole blood)
*buffy coat + erythrocytes = formed elements
Plasma
- 90% water
- Ions (Na+, Cl-)
- Sugars
- Amino acids
- Waste (urea, ammonia, CO2)
- Oxygen
- Hormones
- proteins
3 plamsa proteins
• Albumin
– Keeps water from diffusing out of the vessels
• Globulins
– Antibodies
– Proteins to transport fat, iron and copper
• Fibrinogen
– Helps in blood clotting
Blood Cells
• Most are not true cells – Lack some components – Cannot divide • 3 groups of blood cells: – Erythrocytes – Leukocytes – Platelets
Erythrocytes
• Red blood cells • Most numerous • Biconcave shape for flexibility • No nuclei or organelles – Filled with hemoglobin to carry oxygen
Leukocytes
• White blood cells (complete cells) • Defense • Granulocytes: – Neutrophils – Eosinophils-> turn off allergic response, kill parasites – Basophils-> release histamine • Agranulocytes: – Lymphocytes – Monocytes
Platelets
- AKA Thrombocytes
- Clotting-create a mesh
- Adhere to exposed collagen at the site of the tear to seal it
Common among arteries and veins
• Tunica intima: superficial
- endothelium: smooth muscle
- subendothelial layer
- internal elastic layer (only in arteries, more stretch and recoil)
• Tunica media:
-changes the diameter, artery has elastic fibres
• Tunica externa:
-has collagen fibres, site of platelet attachment
Arteries
• Elastic arteries:
- largest, near the heart
• High in elastin in the walls to dampen blood pressure
- Muscular arteries: smaller, distant
- Thick tunica media allows control of the size of the lumen
- Arterioles: smallest, near tissues
- 1-2 layers of smooth muscle (not as much)
3 types of capillaries
- Continuous: skin/muscle
least permeable, most common, lots of tight junctions - Fenestrated: kidney/small intestine
important in locations with lots of diffusion, fenestration/pores = largest passage of space - Sinusoid: liver/bone marrow/spleen
most permeable, found in spleen and bone marrow where there is need for passage of cells
vascular shunt
bypasses true capillaries
- metarteriole + thoroughfare channel
- used primarily when capillary sphincters are closed
Veins (differences between artery )
- Larger lumen
- Thicker tunica externa
- Less elastin
- Thin walled
- Contain about 65% of the blood at any given time
Vascular Anastomoses
• Similar to a nerve plexus
-junction of blood vessels
• Blood vessels unite and branch so that tissues can
receive blood flow from various vessels
• Protects from damage to individual muscles
Lymphatic System`
• Surrounds capillaries to collect and return excess fluid to the circulation -> Water, small proteins, ions • One-way system towards the heart Order of lymph vessels: • Lymphatic capillaries • Collecting lymphatic vessels • Lymph nodes • Lymph trunks • Lymph ducts
Collecting Lymph Vessels
• Collect lymph from capillaries
• Travel along side blood vessels
• Similar structure to blood vessels, but much thinner
layers
• Contain more valves than veins to prevent back flow
Lymph flow:
• Bulging of muscles/arteries pushes on the vessels
• Tunica media contracts
• Normal bodily movements
Lymph Nodes
• Cleanse the lymph
of pathogens
• Contain many
macrophages
Lymph Trunks
• Lymphatic vessels converge into trunks
- Lumbar trunk – lower limbs
- Intestinal trunk – fatty lymph from digestive tract
- Bonchomediastinal trunk – thoracic organs
- Subclavian trunks – upper limbs, neck
- Jugular trunks – head and neck
