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INTEGUMENT
2 layers – dermis and epidermis; hypodermis not part of skin (areolar CT)
Epidermis
 stratified squamous keratinized epithelium
Dermis
 dense irregular connective tissue (CT) – label tissue, be specific
o not papillary or reticular layer (which might be true but doesn’t answer
question)
o lots of collagen fibers
epidermal-dermal junction
 ridges to protect against shearing forces
 also uses basement membrane (integrins) – Type IV collagen
 dermal papillae with epidermal rete pegs
Thick or glabrous skin – be specific, not just skin or integument
Thin or hairy skin – reduced layers of stratum corneum, no stratum lucidum
 Has hair and sebaceous glands
How to differentiate between thin and thick skin?
* Thickness of epidermis *
Only have two types of receptors to identify
Meissner’s corpuscle
 Mechanoreceptor for light touch
 Located in dermal papillae of papillary layer of thick skin
 Encapsulated, “stripey”
Pacinian corpuscle
 Deep pressure and vibration
 Located deep in hypodermis and lower dermis
 Encapsulated, “onion”
Cytomorphosis – keratinization of keratinocytes
Stratum granulosum – cells are starting to die here
Stratum basale – proliferation of keratinocytes, mitotic activity
Stratum spinosum
Melanocytes
 Cytocrine secretion – melanin transferred to keratinocyte from melanocyte
 Melanin fuses with lysosome, gets degraded by enzymes
Arrector pili muscle – smooth muscle
Hair follicle
 middle – hair shaft
 melanin transfer into keratinocytes, melanocytes in hair matrix
o color of hair depends on type of melanin (tryptophan or tyrosine)
 medulla – soft keratin
 cortex- hard keratin
Identify between internal root sheath and external root sheath
Nails – identify
 nail plate – keratinocytes contain hard keratin
 nail bed – dark layer
 nail root
 nail matrix – where undifferentiated cells are
ALL GLANDS ARE DERIVED FROM EPITHELIUM/ECTODERM
salivary gland – direct nervous stimulation or simple blood vessel dilation
sebaceous gland – gives rise to acne, halfway up hair follicle
Sudiferous glands
APOCRINE sweat glands – with HAIRY SKIN
 axillary, genital areas
 location: jxn of dermis and hypodermis, deep
 large lumen, dumps to hair follicle
 serous, merocrine secretion
ECCRINE sweat gland
 most common, all over body
 small lumen, dumps to surface
 secretory portion – lighter than duct, simple cuboidal,
 duct portion – darker bec has more nuclei, stratified columnar cuboidal (2 layers)
 serous, merocrine secretion
Ducts look same for both sweat glands
CIRCULATORY SYSTEM
Neurovascular bundle – artery, vein, nerve (has no lumen)
Elastic artery (large)
 Aorta, subclavian, common carotid arteries
 Sheets of elastic laminae – internal and external
o IEL – separates tunica intima and media
o EEL – separates tunica media and adventitia
o Collagen Type I and smooth muscle in between sheets
 Tunica intima (endothelial layer), tunica media, tunica adventitia
 Vaso vasorum – vessels to supply vessels
Large vein
 NO internal elastic lamina
 Surrounded by many bundles of smooth muscle in tunica ADVENTITIA
o Runs longitudinally
 Vaso vasorum
Muscular artery (medium)
 Thick internal elastic lamina
 Tunica media >5 layers
 Comparatively thin tunica adventitia
 Round, smaller lumen than accompanying vein
Medium vein
 Larger than muscular artery
 No well-developed tunica media
 Most of wall is tunica adventitia
 Valve
Arteriole
 Tunica media 1-3 layers (smooth muscle)
 Internal elastic lamina
Venule
 Irregular-shaped lumen
 Associated with arteriole (has 1-3 smooth muscle cell layer)
Capillary
 1 endothelial, cell layer - simple squamous
 3 types, depends on basement membrane
o continuous – muscle, connective tissue, gut
 basement membrane is continuous
 MOST COMMON
o fenestrated – endocrine glands, glomeruli in kidney
 basement membrane is continuous
 holes in endothelium cytoplasm
o sinusoidal/discontinuous – liver, spleen, bone marrow, lymph nodes
 basement membrane does not extend between endothelial cells
 liver – cords of hepatocytes, central nucleus in cuboidal cell
 spleen – splenic sinuses
Lymph – single endothelial layer
HEART - identify
 Right atrium – pectinate muscles
 Right ventricle – chordae tendinae
 Left ventricle – papillary muscle
 Left auricle – free standing, unconnected
 Atrioventricular septum – right between atrium and the two ventricles
 Coronary sulcus (atrioventricular) contains
o Right coronary artery
o Circumflex branch of Left coronary artery
o Coronary sinus (posterior)
 Left coronary artery – open connection immediately after aortic valve from aorta
 Pulmonary trunk – hole right next to aorta
 Aorta
o Thicker wall due to high pressure from left ventricle
o Elastic artery – type of vessel
Cardiac skeleton
Forms electrical insulation between atria and ventricles
Holds valves open
Point of insertion for cardiac muscle to tendon
- “chondroid” dense irregular CT, large round cells like cartilage but not
 Annulus fibrosis
o Where semilunar cusps attach
o Fibrous ring
 Septum membranaceum
o CT from trigone down into top of interventricular septum
 Trigones, right and left – CT between vessels
Purkinje fiber
 Individual ones in a bundle between cardiac myocytes
 Large, light-staining cells
o Light bec less myofibrils which are all at periphery
 Basic tissue type – cardiac muscle
o Modified for nerve impulse conduction
 Lots of gap junctions between them
 Look at photo of the fiber in the endocardium, H&E stain
RESPIRATORY
Olfactory epithelium
 DIAGNOSTIC – lots of nuclei layers, 8 or more PCE layers
 Stereocilia, no goblet cells
 Bowman glands – serous, found under PCE (pseudostratified columnar epithelium)
 Vein plexus – supply fluid to Bowman gland and warm/humidify air
PCCE (pseudostratified ciliated columnar epithelium) – respiratory epithelium
 3-4 nuclei layers
Swell bodies - plexus of veins, alternate swelling and deflating with blood to give epithelium
a chance to recover from warming/humidifying incoming air
 In lamina propria, erectile tissue
Epiglottis – core of elastic cartilage
 Lingual surface – stratified squamous epithelium
 Other side – PCCE
 Seromucous gland – dark staining + light staining together
Larynx
Thyroid and cricoid cartilage, hyoid bone, tracheal ring, thyroid, parathyroid, thymus glands
 Thymus – dark cortex, light medulla
 Thyroarytenoid muscle
o From thyroid to arytenoids cartilage in back
o vocalis muscle - medial portion
 True vocal fold – stratified squamous epithelium
 Protect from mechanical trauma of air rushing past
 All the rest – respiratory epithelium (PCCE with goblet cells)
 Vocal ligament – looks like areolar CT, light area above vocalis muscle
Trachea
 Trachealis muscle located next to esophagus (smooth muscle)
 Hyaline cartilage C-ring
 Lined with respiratory epithelium
 Diffuse lymphatic tissue in areas under surface of lumen
o macrophages, lymphocytes within lamina propria
Lung – lacy, identify organ
Bronchi – some hyaline cartilage
Bronchus – hyaline cartilage, columnar cells
 PCCE, lamina propria, submucosa
 Smooth muscle – muscularis
Bronchiole – smooth muscle, NO cartilage or glands
 Primary, terminal, respiratory
 Cuboidal cell everywhere
Alveolar duct
 Long hallway with alveoli, one after another, lining it
 Terminates in alveolar sac
 Atrium – space where all alveoli open into alveolar sac
o Lined with simple squamous epithelium
Terminal bronchiole – lined with smooth muscle
 Pulmonary artery – run with bronchi
 Pulmonary vein – nearby
Alveoli
Alveolar septum
 Surrounds alveolus
 Elastic fibers allow them to stretch for breathing
 Elastic recoil pushes air out of alveoli
Tiny holes – capillary, white lumen
Type II pneumocyte – secrete surfactant, large, round
Type I pneumocyte – lines alveoli
Dust cell, alveolar macrophage – filled with carbon, black
bronchial artery
right – branch off posterior intercostals artery
left – branch off thoracic aorta
BLOOD
Eosinophil
 Red, large granules, uniformly dense
 Bilobed nucleus
 Function: parasites, limit immune response, clean up Ag-Ab complexes
Basophil
 All dark navy
 Large “shards of rock” granules obscuring nucleus
o Granules are NOT uniform
Neutrophil
 Multi-lobed nucleus (up to 5, will not always see all 5)
 Most abundant
 Granular, small granules
Lymphocyte
 Large, acentric nucleus
 Mostly navy blue nucleus, thin layer of cytoplasm
 Slightly larger than RBC (comes in 3 sizes: S, M, L)
 Found in blood smear
Monocyte
 To differentiate from band cell
o MUCH LARGER THAN A BAND CELL, 13 um (almost 2x RBC size)
o FAT, bean-shaped, bi-lobed nucleus
 Lobes overlap, has nucleolus in each (but hard to see)
 Clear, smooth cytoplasm (no granules)
 In blood, transport form of macrophage
o In tissue, termed a macrophage
 Function: phagocytosis
Band



cell
Granular, precursor to Neutrophil
Nucleus indentation goes in far
Very horse-shoe shape
o More cytoplasm between the 2 lobes
o Thinner bridge connecting 2 lobes
 Smaller than monocyte, only 9 um
Platelets – Megakaryocyte is precursor
 Not a cell, cell fragment
 Has a microtubular system
Megakaryocyte
 Biggest cell in blood system
 Multi-lobed nucleus, very dense
 Always near sinusoids where they extrude platelets to circulation
Red bone marrow – identify organ, be specific
 Hematopoietic – filled with stem cells
 Discontinuous capillary/sinusoid
o Found in bone marrow, liver, spleen
RBC production - Erythroblast Islands
Will see small islands of RBC production/development in bone marrow
Located around monocytes called nurse cells, near vasculature
Can see extruded nucleus
Starts blue (due to rough ER) bec need to make lots of protein
Turns purple to pink (due to hemoglobin production)
erythroblast ≠ erythrocyte
No such thing as polychromatophilic erythrocyte
1 – Proerythroblast
 Larger than basophilic erythroblast
 Not as blue bec rough ER machinery not well-developed
 3 nucleoli
2 - Basophilic erythroblast
 More navy blue cytoplasm
 Slightly smaller than proerythroblast
 Stimulated by erythropoietin
 1 nucleoli
3 – Polychromatophilic erythroblast
 Chromatin pattern – not as condensed, nucleus has gaps between chromatin
 Cytoplasm is mix of blue and red: purpley
 Nucleus is centered
4 – Orthochromatophilic erythroblast / Normoblast
 Nucleus condensed/small, very dark
 Pink cytoplasm, less densely stained
 Nucleus off to one side
5 - Reticulocyte
 Special stain shows blue particles (rough ER) within cell
 No nucleus
 Normally only 1% of blood smear
6 - RBC – 7 um
Promyelocyte
 Large, central nucleus, many nucleoli
 Prominent granules in cytoplasm (azurophilic) - HUGE
 Larger cell than proerythroblast
 Clearer cytoplasm
* Prof. Howard mentioned she would not put any of these on the test
Neutrophilic metamyelocyte
 Stage right before band cell
 Not as large as monocyte, though nucleus are similar (fat, U-shape)
o Nucleus not as indented as band cell
 Lots of these when there’s an infection
 Look at neighbor cells – will be surrounded by other WBC development stages like
band cell
Eosinophilic metamyelocyte
 Big red granules
LYMPHATIC SYSTEM
Primary lymphatic organs – bone marrow, thymus
Where B and T lymphocytes grow and mature
Secondary lymphatic organs and tissues – lymph nodes, spleen, lymph nodules
Where most immune responses occur
Mononuclear phagocytic system
Macrophage in liver – von Kuppfer cell
 Phagocytosed special blue dye, has blue spots
 Extends into sinusoids to act as watchguard
 Also near space of Disse (space separating hepatocytes from endothelium of BV)
Diffuse lymphoid tissue – no CT capsule
Solitary nodule – found in respiratory, GI, urinary and reproductive tracts
 Found in all canals open to the external environment
 Usually in lamina propria immediately deep to the epithelium
 Tightly packed, forms a smear
 Primary nodule – absence of germinal center, dark staining, dense, mostly B cells
 Secondary nodule – presence of germinal center due to activation, lighter staining
Trachea
 Identify in photo the lymphoid tissue – the darker areas
Mammary gland
 IgA secreted by plasma cells to give newborns immunity
 Plasma cells come from B cells
o Acentric nucleus – spokes on a wheel
o Found in connective tissue between duct glands
o Cytosol is aqua/carribean blue (cannot tell this color)
MALT – mucosa associated lymphoid tissue
Functions: antigen presentation, phagocytosis
Peyer’s patches (ileum), appendix, tonsils, adenoids
Aggregated nodules together, still no CT capsule
T cell cap – darker, at edge of nodule, T cell predominant
o Always oriented toward lumen of crypt/gut where antigens are recognized
Germinal center – B cell proliferation (not plasma cells), B cell predominant
o Where blast transformation is occurring
M cells
o Antigen-presenting cells, found next to lumen
Peyer’s patches in ileum – likely to be on written test rather than practical (Dr. Howard)
 In lamina propria of GI tract
 Nodules aggregated only one one side, no capsule
 Aggregation of lymphoid nodules in the ileum, usually on side opposite the site of
mesenteric attachment
 HEV (high endothelial venule)
o lined with simple, low, cuboidal epithelium
o where lymphocytes in circulating blood leave the vessel through extravasation
o postcapillary venule
o associated with lymph tissues, conduit to move cells into lymph structures
Appendix
Aggregated nodules go all the way around circumference of lumen in lamina propria
Partially encapsulated lymph tissues
Partial CT capsule on one side, epithelial lumen on other
Has crypts, aggregated nodules, and diffuse lymphatic tissue
Crypts lined with epithelium – type of epithelium designates type of tonsil
Waldeyer’s ring – ring of tonsils
Like a gateway, first line of defense against anything external entering body
Tonsils – based on type of epithelium lining crypt
 Palatine tonsil – stratified squamous mucosal epithelium
 Pharyngeal tonsil/adenoids – respiratory epithelium (PCCE, goblet cells)
o Back wall of nasal cavity
 Lingual tonsil – on tongue, no photos of these
Encapsulated lymph tissues
Lymph node
Cortex + Medulla, bean-shaped organ
Filters lymph
 Cortex – lymph nodules with diffuse lymph tissue in between
 Medulla – lighter staining
o lymph cords - dark staining squiggles, B cell predominant
o lymph sinus - light staining squiggles
 Efferent lymph vessels – Exit lymph node
o Has valves
o Endothelial cells with some connective tissue outside, NO smooth muscle
 Paracortex – between cortex and medulla
o Where HEV (simple low cuboidal cell) are
 T cells exit here from circulation
o Principal cell type – T cell predominant
 Medulla – B cell predominant
 Route of lymph vessels – all one vessel, has different names for different parts
o Afferent lymph vessels all around outer surface, brings in lymph
o CT capsule
o Subcapsular sinus
o Trabecular sinus
 Through paracortex
o Medullary sinus
o Efferent lymph vessel Exit at hilus
o On to next lymph node in series or thoracic/right lymph duct if last node
 Entering lymph encounter: T » B » T » B cells, 99% efficient
Spleen
White pulp & Red pulp
Two functions: filter blood + immune system
 White pulp – dense, blue stain, has central artery
o Immune region, has many lymphocytes
o PALS (periarterial lymphoid sheath) - around central artery in white pulp
 T cell domain in white pulp
 Red pulp– red color, everything else surrounding white pulp
o Blood region, has sinuses
o Contain cords of Billroth – lacy structure between sinuses that filter blood
o Penicillar artery – comes off central artery in red pulp region
 Opens directly to sinusoid (closed) or to red pulp (open circulation)
 Marginal zone sinus – forms border around white pulp, separate white from red pulp
o Where antigens are presented
o Lined by macrophages
 Sinusoids/discontinuous capillaries filter blood like a sieve
o Where antigens are presented
o Lined with endothelial cells, NOT simple cuboidal (HEV)
Thymus
ONLY LOBULATED LYMPH ORGAN
ONLY ONE WITH NO LYMPH NODULES, has lobules instead
ONLY ONE WITH HASSALL’S CORPUSCLES – no known function
 CT in between lobules and lobes
 Each lobule has cortex + medulla
 Function: T cell maturation and proliferation (in cortex)
 Epithelial reticular cells – at edge of lobule, produce hormones for maturation
 T cells migrate from cortex to medulla – 90% killed off
o Leave through postcapillary venules to lymph nodes, Peyer’s patches, etc