Anatomy :( Flashcards
From the inside out what are the four major sections of blood vessels
Lumen, Tunica intima, Tunica media, Tunica adventitia
What are the main components of the tunica intima
Endothelium (simple squamous), Basal laminate of the epithelial cells, Subendothelial connective tissue
What are the main components of the Tunica Media
Smooth muscle fibres in loose connective tissue and potentially elastic fibres
What are the main components of the Tunica Adventitia
Connective tissue which merges with surrounding connective tissue and may also contain vasorum.
What are the main differences between arteries and veins.
Blood pressure, wall thickness, presence of valves
When comparing corresponding arteries and veins how does the artery compare
Arteries have thicker walls, appear to have a smaller lumen, will maintain its shape, more resilient and does not contain valves.
What are the three main types of arteries (and their purposes)
Elastic (conducting), Muscular (distributing), Arterioles (resistance vessels)
How large are elastic arteries and what structural adaptations are present. (Name 3 examples of elastic arteries)
They can be up to 2.5cm diameter and contain a thick tunica media with many elastic fibres and few smooth muscle cells. E.g. aorta brachiocephalic & common carotid.
What is the size range and the structural adaptations of muscular arteries. (Any examples of muscular arteries)
Diameter ranges between 0.5mm - 0.4cm, contain lots of smooth muscle cells in tunica media, distinct internal and external elastic laminae and a thick tunica externa.
How large are arterioles and what structural adaptations do they possess
They are <= 30 μm in diameter and contain only one or two layers of smooth muscle in the tunica media with a poorly defined tunica adventitia
What are the purposes of each of the types of arteries?
Elastic must withstand changes in blood pressure during the cardiac cycle while ensuring blood flow, muscular distribute blood to muscles and organs and will dilate/constrict in order to control blood flow, Arterioles also dilate/constrict and control blood flow and pressure.
What are the structures and purpose of the capillaries
Capillaries connect arterioles and venules (microcirculation) while acting as sites of gaseous exchange. They have slow blood flow and thin walls allowing efficient 2 way exchange of substances. They are only 8μm in diameter.
What are the three types of capillaries and what are their purposes/structures
Continuous (Make up the majority e.g. muscles, CT and lungs)
Fenestrated (pores penetrate endothelial lining which allows for rapid exchange of water and large solutes, mainly used for absorption e.g. kidney, choroid plexus and endocrine glands)
Sinusoidal (Gaps between endothelial cells with an incomplete or absent BM, blood moves slowly through them and large solutes can move in and out. Mainly important in specialised lining e.g. liver)
What is the importance of Metaarterioles and the precapillary sphincter.
A Metarteriole will continue as a thoroughfare channel throughout a capillary bed and has numerous capillaries leading from it, constriction of the metarteriole will reduce blood flow to the entire capillary bed. The Precapillary sphincter can contract and reduce blood flow or relax to increase to the capillary bed.
What is the name and importance of the direct channel from Arteriole to venule
Ateriovenous anastomoses is the channel that connects them and is important as when it dilates it can make blood bypass the capillary bed.
What are the structures and purpose of Venules
They average ~20μm in diameter and will connect capillary beds and small veins, smaller venules are just endothelium on basement membrane and as they get larger they have increasing amounts of smooth muscle outside endothelium
What are the sizes of veins and what are their structural importance
They have 3 categories, small <2mm, medium 2-9mm, large >9mm. They operate at low blood pressure so they are thin walled with a predominant Tunica adventitia with valves to aid flow and prevent back flow.
How do muscles aid blood flow in veins
As muscles especially in the legs contract they will compress the vein slightly and help to “pump” the blood.
In what type of blood vessel is the greatest loss of pressure
Arterioles
In what type of blood vessel is the greatest loss of pressure
Arterioles
Define all locational anatomical terms
Anterior/ventral - The front side of the body
Posterior/dorsal - The real side of the body
Superior - Top half of the body
Inferior - Lower half of the body
Medial - Central pillar of the body
Lateral - To the sides of the body
Proximal - Close to the center of the body
Distal - Far from the centre of the body
What are the three anatomical planes
Transverse/Horizontal - Splits body into lower and upper
Sagittal - Passes from front to back splitting body into left and right
Coronal/frontal - passes from side to side splitting from front to back
What are the different levels of organisation in the body
Cell<Tissue<Organ<System<Organism
What are the 4 types of tissues
Epithelia Connective Muscle Nervous
What are the different types of epithelia
Simple squamous
Keratinised stratified squamous
Stratified squamous
Simple cuboidal
Simple columnar
Pseudostratified columnar with goblet cells
What is the structure and functions of simple squamous epithelia
Flat cells with oval nuclei comprised of one layer. Mainly used for nutrient and gas exchange in blood vessels and alveoli.
What is the structure and function of Keratinised stratified squamous cells
Flat surface with oval nuclei with many layers. Reinforced with keratin making it act as a waterproof barrier e.g. skin.
What is the structure and function of Stratified squamous cells
Flat surface with oval nuclei comprised of many layers, acts as a barrier but non waterproof e.g. oral cavity/oesophagus.
What is the structure and function of Simple cuboidal cells
Square cells with round nuclei with one layer, mainly used for secretion and absorption in glands/kidneys.
What is the structure and function of simple columnar epithelium
Tall cells with oval nuclei nasally located in one layer. Mainly used for absorption and secretion in the GI tract. Have microvilli on the surface.
What is the structure and function of pseudostratified ciliated columnar epithelium with goblet cells
Tall cells that appear stratified because not all cells reach the surface but only one layer of cells. Act as a mucociliary escalator in trachea and large airways.
What are the 4 examples of intercellular junctions
Desmosomes
Hemidesmosomes
Tight junctions
Gap junctions
What is the purpose of gap junctions (and what is the name of the proteins)
(Connexons made of connexins) They allow for rapid intercellular transport of ions and small molecules.
What is the purpose of tight junctions ? (Also known as occlud-adhesion belts)
They seal the apical surface of the cell and prevent other molecules from reaching the basolateral surfaces and potentially damaging them.
What is the purpose of desmosomes and hemidesmosomes
Desmosomes attach to intermediate filaments in the epithelium which stabilise cells against twisting and stretching whereas hemidesmosomes attach to extracellular filaments in the basement membrane.
What are the two sections of the basement membrane (and their structure)
Basal lamina and reticular lamina, the basal lamina is ill organised and secreted by the reticular lamina to act as a selective filter while the basal lamina provides strength.
What is the purpose of systemic circulation
To transport oxygen rich blood from the left side of the heart around the body to the body tissue.
What are the names of some of the major blood vessels and location
(Use internet to check)
What is the purpose of pulmonary circulation
Takes deoxygenated blood out of the right side of the heart to the lungs then returning to the heart.
What is the function of the lymphatic system
Supports the immune system and provides a mechanism for drainage of interstitial fluids
How does capillary blood pressure and Blood colloid osmotic pressure change across a capillary bed.
Blood pressure drops while osmotic pressure is constant therefore at the start substances move out of the capillaries then, it is re absorbed later due to osmotic pressures as blood pressure drops.
How much fluid is reabsorbed by the capillaries and lymphatic vessels respectively
85% by capillaries 15% by lymphatic vessels (must = 100% otherwise oedema will result).
What is the pathway of lymph through the lymphatic system
Absorbed into lymph capillaries -> lymph vessels -> lymph nodes -> lymph trunks -> thoracic duct or right lymphatic duct -> back into circulation
Where do the two lymph ducts drain from and into
Right lymphatic duct drains from the right side of head and thorax into right subclavian vein and thoracic duct drains from everywhere else into left subclavian vein.
What are fibroblasts and where are they present
They are cells that create proteoglycans to help make the ground substance viscous in connective tissue. They also secrete protein substances to help make fibres that support the matrix.
What are fibrocytes and where are they found
They are similar to fibroblasts but instead they maintain the fibres present rather than secrete viscous proteoglycans
What are adipocytes and where are they found
Also known as fat cells these cells are important stores of fat and contain a giant lipid droplet . They are found in connective tissue
What are mesenchymal cells and where are they found
They are found in connective tissue and will reproduce then differentiate into cells in the case of injury or infection
What are melanocytes and where are they found
They are found in connective tissue and contain the pigment melanin responsible for giving tissue their dark colours
What are macrophages
Present in the connective tissue as both fixed and free, they are large phagocytic cells responsible for responding to and engulfing pathogens.
What are mast cells and where are they found
They mature in blood vessels until moving into vascularised tissues. They contain large amounts of histamine and heparin, histamine stimulates inflammation and heparin acts as an anticoagulant.
What are the three types and properties of connective tissue fibres
Collagen - thick, strong but flexible (Not stretchable) fibres
Reticular - similar to collagen but forms thin fibres in networks sued to stabilise organs and tissue
Elastic - Capable of being stretched and being returned to its original state.
Where is loose connective tissue found and what is its purpose
Lots of ground substance
Few fibres and high cell variety
Found under epithelium
Where is dense irregular connective tissue found and what is its structure
Little ground substance
Lots of collagen bundles arranged messily
Few cells mostly fibroblasts
Found in the dermis
Where is dense regular connective tissue found and what is its structure
Low amounts of ground substance
Densely packed parallel rows of collagen fibres
Mostly fibroblasts
Found in tendons and ligaments
What is the importancevof skeletal muscle
Moves and stabilises skeleton, forms sphincters in digestive/urinary tracts and helps with respiration.
What is the estructure of skeletal muscle
Long cylindrical cells that are striated (striped). Multiple nuclei; innervated by somatic nervous system.
What is the importance of smooth muscle
Located in the walls of organs, blood vessels and airways. Important for gastrointestinal movement (peristalsis). Alters diameter of airways and blood vessels.
What is the structure of smooth muscle
Short fusiform cells; non-striated (not striped); single central nucleus and innervated by autonomic nervous system.
What is the structure and importance of cardiac muscle
It is the muscle tissue in the heart and is comprised of striated, branched muscle fibres. There are 1-2 central nuclei, intercalated discs and it is innervated by the autonomic nervous system.
What is a secondary function of lymph (other than immune response and draining tissue fluid)
Transporting dietary lipids and lipid soluble nutrients
Where is the heart located
To the left of the center of your body between the 2nd and 5th ribs, the apex rests in the 5th intercostal space
What is the outermost covering of the heart
Fibrous pericardium, an inelastic, dense connective tissue that is connected to the diaphragm and the great vessels.
Why is the fibrous pericardium important
It prevents overfilling of the heart and provides structural anchorage
What are the inner layers of the pericardium
Parietal (lines inner surface of fibrous pericardium)
Visceral (epicardium that adheres to the heart)
Pericardial cavity (space between the two layers containing pericardial fluid to reduce friction)
What are the three layers of heart walls
Endocardium - endothelium
Myocardium - cardiac muscle
Epicardium - visceral pericardium
Why is fibrous connective tissue in the heart vital
it electrically isolates the atrium from the ventricle prevent them from contracting simultaneously. It forms bands between atria and ventricles, encircles the pulmonary trunk/aorta and suspends the valves.
What connects and controls the valves
Chordae tendinae connect the valve to the papillary muscles which contract to prevent the valves from inverting allowing back flow.
Try and label a diagram of coronary circulation
(Look online i ain’t paying for premium)
Rate how right you got it (online again)
Describe the path of the cardiac conducting system
It enters at the sinoatrial node where the atrium is stimulated causing atrial contraction, then the signal is transported to the AV node where a slight delay occurs ensuring atrial contraction has completed. Then finally ventricular contraction is caused by the signal travelling down the bundle of his then along the Purkinje fibres to the ventricular walls.
What are the three shortcuts of foetal circulation
Foramen ovale - connects left and right atria
Ductus arteriosus - connects aorta and pulmonary trunk
Ductus venosus - connects umbilical cord to inferior vena cava bypassing liver
What happens to the three foetal shortcuts at birth?
Ligamentum arteriosus - constricts and doesn’t allow blood flow anymore
Fossa ovalis - comes from foramen ovale after it closes
Ligamentum venosum - fibroses as the umbical cord is tied and closed
