BL Flashcards
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
IV- BM
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
Where are follicular DCs?
In germinal centres, can cause B cell prolif
Functions of spleen
Destroys RBCs, antigen presentation, B and T cell activation, macrophages remove antigen from blood
What happens following splenectomy?
BM and liver can take over destroying RBCs, but increased risk of encapsulated (meningococcus) and malaria infection, increased risk of DVT and PE (maybe due to increased platelets?)
When can the spleen enlarge?
In response to systemic infection e.g. glandular fever, malaria, septicemia
When the thymus involute?
After puberty, by late teens is mostly fat
Where do neutrophils, mast cells, monocytes and basophils come from?
Myeloblast, which comes from a common myeloid progenitor
Where is McBurney’s point?
Between umbilicus and ASIS, 2/3 from umbilicus
What occurs at the sternal angle?
T4/5 level, 2nd rib, aortic arch, tracheal bifurcation
What occurs at the level of the umbilicus
L3/4, bifurcation of aorta
Top of iliac crest is which level?
L4
Where is BM harvested from?
Iliac crest
Name layers of the gut mucosa
Epithelium, lamina propria, muscularis mucosae
What are serous membranes?
2 part membranes that line body cavities that don’t open to exterior- peritoneum, pleural sacs, pericardial sac. Has epithelial layer and thin CT layer
What is mesothelium?
Simple squamous epithelium lining the pleural sac, pericardium and peritoneum
Name locations of simple squamous epithelium
Blood vessels (endothelium), pericardium/pleural sac/peritoneum (mesothelium), loop of henle, Bowman’s capsule, pulmonary alveoli
Functions of simple squamous epithelium
Barrier (Bowman’s capulse), lubrication (mesothelium), gas exchange (alveoli)
Where are simple cuboidal cells found?
Lines pancreatic duct, surround thyroid glands and synthesise thyroxine, CDs of kidney, surface of ovary
Functions of simple cuboidal cells?
Absorption and secretion in exocrine glands and kidney tubules, covering ovary, synthesis of thyroxine
Where are simple columnar cells found?
Fallopian tubes, colon
Where are simple columnar cells with microvilli found?
Jejunum
Function of simple columnar cells?
Absorption, secretion and lubrication in SI&LI, transport in fallopian tubes
Where is pseudostratified epithelium found?
URT (with cilia), nasal cavity, parotid gland, epididymis, vas deferens
What are functions of pseudostratified epithelium?
Mucus secretion and particle trapping and removal (URT),
Where are stratified squamous cells found?
Vagina, skin, oesophagus, oral cavity
Name layers of epidermis
Stratum corneum, granular layer, prickle cell layer, basal layer dermis
Why is the basal layer important in the epidermis?
Keratinocyte mitosis occurs here, then move upwards to the prickle layer where they terminally differentiate
What happens in the granular layer?
Keratinocytes lose their plasma membrane and become corneocytes
How long does it take for a keratinocyte to move upwards to the stratum corneum?
28-40 days
Name cells of the epidermis
Keratinocytes, corneocytes (in stratum corneum), Langerhans, melanocytes
What is transitional epithelium?
Stratified epi that can change shape from cuboidal/columnar to flat
Where is transitional epi found?
Ureter, bladder, urethra, renal calyces
Name a unicellular gland
Goblet cell!
What effects can CF have on GI?
Meconium ileus, constipation, poor absorption
What are merocrine, apocrine and holocrine secretion?
Merocrine is exocytosis, apocrine is droplets covered with plasma lemma e.g fat droplets in milk, holocrine is whole cell breakdown e.g. sebaceous gland of skin
Name some tubular glands
Intestinal crypts, gastric pits
What effects can CF have on pancreas?
Exocrine secretions are dehydrated, become thick and block the ducts, pancreatitis and fibrosis, poor absorption due to blocking enzymes
<5mm lump =
papule
5-10mm lump=
nodule
small water blister =
vesicle
larger water blister -
bulla
pus filled vesicle =
pustule
thread vein =
telangiectasia
non palpable area of discoloration =
macule
macule >2cm =
patch
palpable, flat topped area >2cm =
plaque
loss of epidermis
erosion
loss of epi and dermis
ulcer
What pathology is involved in psoriasis?
Rapidly proliferation in basal layer, desquamation of stratum corneum, leukocytes infiltrate
Thickening of the skin =
lichenification
Name the 3 types of cartilage
Hyaline, elastic, fibrocartilage
What is the only cell type found in healthy hyaline cartilage?
Chondrocytes
What cell type produces ECM in the cartilage?
Chondrocytes
Difference between collagen and cartilage?
Collagen is a type of fibre found in CT. Cartilage is a type of CT. Type II collagen is found in hyaline cartilage.
How do GAGs attract water?
They have lots of negative charges
Describe the structure of the three types of cartilage
Hyaline- type II collagen, GAGs, hyaluronic acid
Elastic- hyaline + elastin fibres
Fibrocartilage- hyaline + type I collagen