Body Logs Flashcards
Cellular components of blood
Red cells: erythrocytes, reticulocytes
White cells: Lymphocytes- B and T cells
Eosinophil- eosinophilic granules, bilobular, phagocytose pathogens
Basophil- bilobed nucleus, purple granules contain histamine+ heparin- triggers inflammation
Neutrophil- multilobed nucleus, kills bacteria
Monocyte- unilobular horseshoe nucleus, phagocytose+ present antigens
Platelets- biconvex, aggregate to clot, contain clotting factors
GI tract layers
Muscosa: epithelial lining+ mesenchymal layer
Muscularis mucosa: thin discontinuous smooth muscle layer
Submucosa: connective tissue layer w/ arteries+veins
Muscularis externa: contains inner circular muscle+ outer longitudinal muscle
Serosa: connective tissue w/ collagen+elastin fibres, some vessels+nerve fibres
Epithelial cell adherence systems
Tight junction: towards apical end of lateral surface, opens to allow paracellular transport
Adhesion junction/belt: ~1/3 from luminal surface, E-cadherin proteins attached to intracellular actin filaments
Gap junctions: open to allow free movement of small molecules
Desmosomes: E-cadherins proteins connect to intracellular cytokeratin- only adhesion in epidermis
Cell adhesion molecules: integrins, selectin, CAM
Basal surface: hemi-desmosome, focal adhesions (actin filaments to integrins), integrins (alpha-eta dimer, binds extracellular matrix, focal adhesion kinase phosphorylates producing heterotetramer)
Types of epithelium+ example in the body
Simple squamous: e.g endothelium, walls of alveolus
Simple cuboidal: e.g exocrine glands, kidney collecting ducts
Simple columnar: e.g intestines, stomach lining+ gastric glands
Pseudostratified: all cells touch basement membrane but different nuclei levels and different heights, e.g upper respiratory tract
Stratified squamous non-keratinised: e.g vagina, oral cavity, oesophagus
Stratified squam keratinised: e.g epidermis
Transitional: surface cells vary from columnar/cuboidal (when relaxed) to flattened (when stretched) e.g urothelium
Gland generation
- Growth signal is received
- Proliferation of daughter cells+ extracellular protein degradation enzymes produced
- Epithelial cells invade space created
(If exocrine) central cells die off (canalicularisation produces a duct)
(If endocrine) angiogenic factors stimulate blood vessel growth, link to mother epithelial cells broken via apoptosis
Collagen types
Type 1: b(one) (also dense CT)
Type 2: car(two)lage
Type 3: reticulin (fibres around vessels, nerves, tendons)
Type 4: floor (basement membrane of epithelial cells)
Smooth muscle contraction
Caveolae bring signals to myofilaments by pinocytosis
Causes dense bodies to join with dense plaques
Contraction occurs in direction brought together (occurs in all directions)
Bone formation (endochondral ossification)
- Periosteal bone appears at shaft of cartilage bone model
- Central cartilage calcifies, nutrient artery penetrates, primary ossification centre formed
- Medulla comes cancellous bone, cartilage forms epiphyseal growth plates, secondary ossification centres form on epiphyses
- Epiphyses ossify and growth plates extend bone, growth plates replaced by bone
Bone formation (intramembranous ossification)
- Mesenchymal stem cells congregate, become osteoprogenitor cells, then osteoblasts
- Osteoblasts lay down osteoid, osteoid mineralises forming spicules
- Spicules join to form trabeculae- merge to form woven bone. Trabeculae replaced by lamellae of mature compact bone
Movement of vesicles in neurons
Kinesin travels in the anterograde direction with vesicles and mitochondria
Dystrin travels in the retrograde direction with empty vesicles
Glial cell types
Astrocyte: perivascular feet contain gap junctions- transport of nutrients from blood to neurone+ support
Satellite cell: similar role to astrocyte, surrounds sensory neurone cell bodies
Ependymal cell: epithelial cell lining spinal canal+ brain ventricles. Synthesise+ secrete CSF, microvilli take up CSF to present pathogens to microglial cells, cilia move CSF
Microglial cell: CNS macrophage
Oligodendrocyte: CNS Schwann cell, surrounds multiple neurones
Mechanoreceptor types+ types of hair
Meissner corpuscle- detects tapping+ flicking movements
Parcinian corpuscle- detects vibration+ pressure
Ruffini’s corpuscle- joint movement+ tissue stretch
End bulb- thermoreceptor
Nociceptor- registers pain
Root hair plexus- vibration in the hair shaft
Lymph node structure
Multiple afferent lymph vessels that enter via convex surface
Singular efferent lymph vessel leaves via concave hilum
Feeding artery+ draining vein enter and leave via hilum
Epidermis layers
Come Let’s Get Sun Burnt
Stratum corneum: outer layer made of squames, continuously shed
Sratum leucidum: ONLY on palms and soles of feet
Stratum granulosum: stratified squamous epithelium, lamellar granules (assemble+ secrete keratin fibrils), tonofibrils (keratin filaments+ keratohyaline granules), Golgi appears increased
Stratumm spinosum: cuboidal epithelium, produces lamellar bodies
Stratum basale: melanocytes present, columnar epi cells, renews keratinocytes
