Blood And Blood Vessels Flashcards
What is the path taken by blood to arrive at capillaries
Arteries
Elastic arteries
Muscular arteries
Arterioles
Meta arterioles
What is the path taken by blood LEAVING the capillaries
Post capillary venule
Veins
What is the structure of the tunica intima (inner layer) of a blood vesicle
Endothelial cells supported by a basal lamina and thin layer of connective tissue
What is the structure of the tunica media (middle)
smooth muscle
What is the structure of the tunica adventitia
Made up of supporting connective tissue
How is the tunica intima seperated from the media
Layer of elastic tissue called the internal elastic membrane
How is the tunica media separated from the adventitia
External elastic membrane
How are elastic fibres stained
Using special stains (H or E won’t work)
How do larger arteries differ to general arteries
tunica media has sheets of elastic fibres not smooth muscle
How does the outer part of the artery wall obtain nutrients in elastic (large) arteries
Vaso vasorum
How do the inner layers of artery walls obtain nutrients
Diffusion as they are closer to lumen
What happens to the structure of arteries as they become smaller
Lose smooth muscle - only 1 or 2 layers in media and very little adventitia
What is the structure of a terminal arteriole
No internal lamina
Covered by continuous coat of smooth muscle cells
What is the structure of a meta arteriole
non-contractile cells called pericytes access capillaries
What is the structure of a capillary
Composed of endothelial cells and a basal lamina
Receives nutrients by diffusion
What structures are capillaries absent in
Epidermis of skin, hair and nails
Hyaline cartilage
What are the 3 types of capillary
Continuous (epithelial)
Fenestrated
Discontinuous/sunusoidal
Where are continuous capillaries found
Muscle
Nerve
Lung
Skin
What is the function of fenestrated capillaries
Gut mucosa
Endocrine glands
Kidney
What is the structure of fenestrated capillaries
contain small pores
What is the structure of discontinuous capillaries
Have large gaps in membrane
Where are discontinuous capillaries found
Liver
Spleen
Bone marrow
What is the function of precapillary sphincters
help to control the flow through the network
Composed of smooth muscle
Why are post-capillary venules important
Important sites for exchange i.e. cell moving into tissue for inflammation
When are vessels considered venules
When they acquire intermittent smooth muscle cells in the tunica media layer
What is the structure of a vein
Tunica intima
Thin tunica medica
Large tunica adventitia
What is the function of the lymph vascular system
Drain excess tissue fluid into the blood stream
Transports lymph to lymph nodes
What is the structure of lymphatic vessels
Thin walled
No central pump
contains smooth muscle in walls
How do lymphatic vessels produce flow
Compression of vessels (voluntary muscle)
Hydrostatic pressure in tissue
Where is the majority of blood found in the body
Peripheral veins (65%)
What are the components of the blood
Formed elements
Plasma
What do ‘formed elements’ in the blood consist of
Red cells
White cells
Platelets
What proteins are found in blood plasma
albumin
clotting factors
What does blood plasma consist of
Water
Proteins
Nutreints
Salts
What are the 2 types of white cells
Granulocytes (lots of granules in the cytoplasm)
Agranulocytes
What are the types of granulocytes
Neutrophils
Eosinophils
Basophils
What are the types of agranulocytes
Lymphocytes
Monocytes
How does blood separate in a centrifuge
Red cells are densest, found at bottom
Then white cells
Plasma at top
How is serum extracted
allow blood to clot first then remove the clots
When is plasma considered serum
If clotting factors are removed before centrifuge
What are the characteristics of erthyrocytes (red blood cells RBC)
No nucleus or organelles
1/3 taken up by haemoglobin
flexible
How long do erythrocytes last
4 months
Removed by spleen and liver
What is the most common type if leukocytes (white blood cells)
Neutrophils - 40-75%
What are neutrophils activated by
bacteria
What are the characteristics of neutrophils
Granules
Multi-lobed nucleus
Produced in bone marrow
What are the characteristics of eosinophils
Granules containing hydrolytic enzymes
Released form marrow, circulate then move into tissue
What is the function of eosinophils
fighting parasitic infection
What are the characteristics of basophils
Least common granulocytes
Affinity for basic dyes (purple)
Bilobed nucleus
What are the functions of basophils
Effector cells in allergic reactions
Release granules
When do monocytes become macrophages
when in tissues
What are the characteristics of monocytes
Numerous small lysosomal granules
Non-lobulated (kidney shaped) nucleus
What makes up the mononuclear phagocyte system
Monocytes and macrophages
Members ‘wander’ around body/tissues
What are the characteristics of lymphocytes
No visible granules
B cells and T cells (cant distinguish via stain)
Arise in bone marrow
Where do T cells differentiate
Thymus
What is the B cell immune response
Give rise to antibody secreting plasma cells
What is the T cell immune respone
Form a complex set of cells that perform defence functions such as killing defective cells
What are platelets
Small cell fragments found in blood
Play key role in the prevention of blood loss (hemostasis)
What is the structure of a platelet
Well developed cytoskeleton
Some organelles, no nucleus
Granules containing some coagulation factors
How does blood formation change through development
Bone marrow produces blood by birth
Bones expand, hemopoiesis (production of blood) shut down in many bones
Which cells produce platelets
Megakaryocytes - large cells of bone marrow that platelets fragment off from
can you distinguish between lymphocytes in routine stains
no
