Flashcards in BL Deck (212)
How do cells attach to the BM?
Hemidesmosomes OR focal adhesions (intracellular actin filaments connected to integrins which connect to the ECM)
2 main functions of integrins
Attach the cell cytoskeleton to the ECM, signal transduction from the ECM to the cell
Give examples of static, stable, and labile cells
Static/permanent: don't regenerate, CNS, cardiac and skeletal myocytes
Stable: regenerate when necessary e.g. fibroblasts, endothelium, SM cells
Labile: constantly multiply with short lifespan e.g. blood, epithelium
Differences between prokaryote and eukaryote
Pro: no nucleus, no mitochondria, cell wall
Where are stereovilli found?
Middle ear hair cells and epididymis
Where are cilia found?
Fallopian tube, bronchioles
Name three fibres in CT and their functions
Collagen (high tensile strength and flexible), reticular (supporting framework), elastin (allows recoil)
What is ground substance
Viscous, high water content, contains proteoglycans (which are core protein + GAGs)
Name a glycosaminoglycan and what it does
Hyaluronic acid- attracts water, bound to proteoglycans, in the ground substance of cartilage, because of its swelling it resists compression
What is a proteoglycan
core protein + GAGs attached
Describe structure of types of CT proper (general CT)
Loose: sparse collagen, many cells, lots of ground substance, viscous
Dense: lots of collagen, few cells, not much ground substance
What is the main role of loose CT and therefore where is it found
Good at transport/diffusion because lots of ground substance and viscous, so located beneath epithelium or around small blood vessels
Describe the structure of types of dense CT
Regular has collagen in parallel bundles with fibroblasts in between to withstand stress in a single direction ie. tendons, ligaments, aponeuroses. Irregular has collagen in multiple directions with fibroblasts between for stress in multiple directions e.g. submucosa of intestine, deep layers of dermis.
What is the structure of collagen in ligaments?
Densely packed in parallel bundles but undulate (like super noodles) and arranged in fascicles separated by loose CT
What is an aponeurosis? and name one
Flat sheet of dense regular CT with bundles of fibres in one layer arranged 90 degrees to adjacent layers e.g. linea alba
Name the layers of the abdominal wall in order
Skin, SC fat, external oblique, internal oblique, rectus abdominus, transversus abdominus
What type of CT is the dermis?
Dense irregular (resists multiple stress directions)
What do fibroblasts do?
Synthesis ground substance, procollagen, GAGs, glycoproteins
Important in wound healing and scar formation
Myofibroblasts contain actin and do wound contraction
What types of collagen are there and where are they found
I- fibrils aggregate into fibres: skin, tendon, bone
II-fibrils do not form fibres (hyaline and elastic cartilage) cartilage
III-Fibrils form fibres around structures (reticulin)blood vs, LN capsule
What is the structure of type I collagen?
Triple helix of a chains
What do you need vitamin C for?
The intracellular production of procollagen by fibroblasts
What is Marfan's syndrome?
AD problem with fibrillin so elastic tissue is abnormal (abnormally tall, frequent joint dislocation, arachnodactyly, risk of aortic rupture)
Where is elastin found?
Tunica media of aorta (produced by SM cells) and lungs
Difference between white and brown adipose cells?
White contain one lipid droplet with nucleus pushed to the side, role in fuel reserve, thermal insulation, shock absorption.
Brown contain many lipid droplets and a central nucleus, especially found in newborn close to scapula, sternum, axillae, also present in upper chest and neck of adults, in thermogenesis
Why are brown fat cells brown?
Rich vascular supply and abundant mitochondria
Tell me about ghrelin and letpin
Ghrelin released from stomach and signals hunger, leptin released from adipose cells to tell you to stop eating
Explain the difference between CT, collagen, and cartilage
CT is loose or dense and a major group of body tissue types
Collagen is one fibre of CT (the others are reticular and elastin)
Cartilage is a type of CT that has type II collagen
Name components of the lymphatic system
MALT, GALT, tonsils. Peyer's patches (ileum), LNs, thymus, spleen
How does lymph move?
Deep lymphatics moved by adjacent muscles, abdo/thorax large lymphatics have SM in their walls