Histology Lectures Combined Flashcards
(103 cards)
1
Q
Identify the 5 layers of the epidermis in thick skin (palms)
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2
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Shows the small intestine and the lamina propria
* Def: thin layer of loose, connective tissue, blood vessels, and nerve endings; immediately under the epithelial surface
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C= capillary
F = fibroblast
* Connective tissue is primarily made up of the ECM
* ECM has organized bundles of fibers (pink)
* Ground substance is pale
4
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Three components of ground substance
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Ground substance:
1. Glycosaminoglycans (hyaluronic acid & the sulfates)
2. Proteoglycans
3. Glycoproteins (fibronectin, laminin)
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Collagen type I
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Reticular fibers (type III collagen)
* Found in the bone marrow, lymph nodes, spleen, skin, smooth muscle cells
7
Q
Basal cell carcinomas usually start in the _ layer of the skin
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Basal cell carcinomas usually start in the basale layer of the skin
* Develop on skin exposed areas
* Slow growing
8
Q
Squamous cell carcinoma is found in _ layer of the skin
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Squamous cell carcinoma is found in the outer layers of the epidermis
* Continuously sloughed off
9
Q
Which skin type lacks hair follicles and sebaceous glands?
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Thick skin
10
Q
What is the structure marked As?
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Eccrine sweat gland (coiled)
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12
Q
The _ are the most predominant cell type in the epidermis; they are mitotically active and helping the dermis to regenerate every 30 days
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The keratinocytes are the most predominant cell type in the epidermis; they are mitotically active and helping the dermis to regenerate every 30 days
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What do we mean when we say basal keratinocytes or basal cells?
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Basal keratinocytes or basal cells are keratinocytes on the basement membrane
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16
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_ is an autoimmune disease against desmoglein
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Pemphigus vulgaris is an autoimmune disease against desmoglein
* Desmoglein is a component of desmosomes
17
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(Pemphigus vulgaris/ Bullous Pemphigoid) is potentially fatal
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Pemphigus vulgaris is potentially fatal
18
Q
Bullous pemphigoid is an autoimmune disease against _
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Bullous pemphigoid is an autoimmune disease against hemidesmosomes
* Less severe than pemphigus vulgaris
19
Q
_ usually presents with flaccid bullae in the skin and oral mucosa
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Pemphigus vulgaris usually presents with flaccid bullae in the skin and oral mucosa
20
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_ usually presents with tense bullae in the skin but not oral mucosa
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Bullous pemphigoid usually presents with tense bullae in the skin but not oral mucosa
21
Q
Where do we find melanocytes?
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Melanocytes are found in the stratum basale
* They synthesize melanin in melanosomes and transfer it to adjacent keratinocytes
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24
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Langerhan cells
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Langerhan cells are dendritic cells
* Appear primarily in the stratum spinosum
* But can be in any epidermal layer
* Appear pale with “comma like” cytoplasmic process and indented nucleus
* Have birbeck granules
* They act as antigen-presenting cells in immune responses
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We find merkel cells in the _ layer
We find merkel cells in the **stratum basale**
* Sensory mechanoreceptors
* Pale cytoplasm + dense cored granules
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The _ layer contains proteins that bind keratin filaments together
The **stratum granulosum** layer contains proteins that bind keratin filaments together
* Within **keratohyalin granules**
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What is a unique finding in the stratum spinosum?
Keratinocytes contain **membrane-coating granules** and are connected to one another via desmosomes
* Granules are releasing lipids between cells to create impermeability to water
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Classify the type of connective tissue of the epidermis
**Epidermis** is stratifed squamous keratinized epithelium
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Classify the type of connective tissue of the dermis
**Dermis** is dense, irregular connective tissue
33
What are the structural components of the papillary layer?
**Papillary layer**: thin, loosely arranged fibers
* Type I collagen
* Type III collagen
* Elastic fibers
* Contains meissner corpuscles (fine touch)
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What are the structural components of the reticular layer?
**Reticular layer** has dense collagen bundles and thick elastic fibers
* Type I collagen
* Arteries, veins, lymphatics
* Pacinian corpuscles (pressure, vibration)
* Sweat glands, hair follicles, sebaceous glands
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Vascular Ehlers-Danlos syndrome is a deficiency in _
**Vascular Ehlers-Danlos** syndrome is a deficiency in **type III collagen**
* Blood vessel aneurysms, organ rupture
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Classical Ehlers-Danlos syndrome is a deficiency in _
**Classical Ehlers-Danlos** syndrome is a deficiency in **type V** collagen
* Hyperextensible skin, hypermobile joints, joint dislocation, tendency to bleed, easy bruising
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A patient presents with history of organ rupture and easy bruising; they may have _
A patient presents with history of organ rupture and easy bruising; they may have **vascular EDS** (problem with type III collagen)
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A patient presents with hyperextensible skin, tendency to bleed, and joint dislocation; they may have _
A patient presents with hyperextensible skin, tendency to bleed, and joint dislocation; they may have **classical EDS** (issue with type V collagen)
39
What is the secretory mechanism of eccrine sweat glands?
Exocytosis or **merocrine**
40
Characterize the secretions from eccrine sweat glands
Eccrine sweat glands secrete **mucinogen-rich** product and **watery electrolyte-rich** material
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Characterize the secretions from apocrine sweat glands
Apocrine sweat glands secrete **viscous secretions** onto hair follicles where the bacteria acts --> odor
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Sweat glands are under sympathetic control and are (cholinergic/ adrenergic)
Sweat glands are under sympathetic control and are **cholinergic**
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Papillary dermis (left)
Reticular dermis (right)
44
What type of gland are the sweat glands?
Sweat glands are **simple coiled tubular glands**
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What type of glands are sebaceous glands?
Sebaceous glands are **branched acinar glands**
* The duct empties into the neck of a hair follicle
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Sweat glands are found in _ layer of the skin
Sweat glands are found in **reticular dermis** layer of the skin
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Sebaceous glands are found in the _ layer of the skin
Sebaceous glands are found in the **reticular dermis** layer of the skin
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_ is a smooth muscle that elevates the hair and is sympathetically innervated
**Arrector pili muscle** is a smooth muscle that elevates the hair and is sympathetically innervated
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Apocrine gland
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Sebaceous gland
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What is the function of the following?
Meissner corpuscle: function in fine touch perception
* Dermal papillae of thick skin, eyelids, nipples
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What is the function of the following?
**Pacinian corpuscles** are found deep in the dermis/hypodermis and they are especially abundant in the breasts and digits
* They percieve *pressure, touch, vibration*
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Where do we find the following?
We find **free nerve endings** around *hair follicles* and in the *trachea* in the dermis layer
* Function in sensing pain, heat, touch
* **F**ree **N**erve endings = **F**ire (heat) and **N**ocioception (heat)
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What is the function of the following?
**Merkel disks** provide information on pressure, position, and static touch (recognizing shapes and edges)
* Located in the epidermis near follicles
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Ruffini's endings sense _
**Ruffini's endings** sense pressure and touch
* Found in the dermis and joints
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Which disease might be associated?
**Scurvy**- corkscrew hair
* Other signs: bleeding gums, tooth loss, bruising and poor wound healing, weakened immune response, thin appearance
* Administer vitamin C
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Bone has _ collagen
Bone has **type I** collagen
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Dentin has _ collagen
Dentin has **type I** collagen
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Ligaments have _ collagen
Ligaments have **type I** collagen
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Dermal-epidermal junction has _ collagen
**Dermal-epidermal junction** has have **type V** collagen
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Bone marrow has _ collagen
Bone marrow has have **type III** collagen
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Basal lamina of the basement membrane has _ collagen
Basal lamina has have **type IV** collagen
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Organ capsules have _ collagen
Organ capsules have have **type I** collagen
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The vitreous body has type _ collagen
Vitreous body has have **type II** collagen
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The cornea of the eye has _ collagen
Cornea has have **type I** collagen
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Hyaline cartilage, elastic cartilage, and fibrocartilage have _ collagen
Hyaline cartilage, elastic cartilage, and fibrocartilage have **type II** collagen
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The nucleus pulposus has _ collagen
The nucleus pulposus has **type II** collagen
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Smooth muscle cells have _ collagen
Smooth muscle cells have **type III** collagen
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Elastic fibers are composed of _ and _
Elastic fibers are composed of **elastin** and **fibrillin**
* These get synthesized by fibroblasts, smooth muscle cells, chondrocytes/chondroblasts
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What is the following?
Elastic fibers
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Steps of collagen synthesis
1. Collagen mRNA is made in the nucleus --> travels to the rough ER
2. Pre-procollagen (alpha chains) gets created
3. Hydroxylation of Pro (P) and Lys (K) **Must have Vitamin C as cofactor for hydroxylation**; lacking vitamin C = scurvy
4. Glycosylation of hydroxylysines
5. Procollagen triple-helix forms (3 alpha-chains align and coil)
6. Carbohydrates get added
7. Secretion is by exocytosis
Out of the cell:
1. Procollagen is cleaved into tropocollagen
2. Tropocollagen assembles into collagen fibrils (cross-linking)
**Defects in these extracellular events can lead to EDS**
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Swollen gums, poor wound healing, bruising can be signs of _
**Scurvy!**
* Decreased hydroxylation of pro and lys
* Decreased collagen synthesis and weak collagen
78
Defects in formation of the triple helix of procollagen can result in _
**Osteogenesis imperfecta!**
Decreased formation of procollagen:
* Multiple fractures in childhood
* Blue sclerae
* Hearing loss (ossicles of ear)
* Abnormal teeth (lack of dentin)
79
Osteogenesis imperfecta is a decrease in type _ collagen and results due to a defect in _ formation
**Osteogenesis imperfecta** is a decrease in **Type I** collagen and results due to a defect in **procollagen (triple helix)** formation
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Ehlers-Danlos syndrome is a genetic disease that results from a defect in type _ or type _ collagen
EDS: defect in type III or type V
**Type III**: aneurysms of various vessels, organ rupture
**Type V**: hyperextensible skin, hypermobile joints, joint dislocation, tendency to bleed, bruising (epidermal-dermal junction)
81
What happens if we have a defect in type IV collagen?
**Type IV collagen** is found in the basement membrane
* **Alport syndrome**: kidneys, hearing, eyes affected; "can't see, can't pee, can't hear a bee"
* **Goodpasture syndrome**: pulmonary alveoli, renal
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A patient has impaired kidney function, hearing loss, and eye problems; they may have _
A patient has impaired kidney function, hearing loss, and eye problems; they may have **Alport syndrome**
* "Can't see, can't pee, can't hear a bee"
* Defect in type IV collagen
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Marfan syndrome results from mutations in genes encoding _
Marfan syndrome results from mutations in genes encoding **fibrillin** which is important part of *elastic fibers*
* Long, slender limbs and fingers
* Lens of eye dislocated
* Cardiovascular problems (aorta rupture)
84
How can we identify pericytes?
**Pericytes** support capillaries; they sit on the capillaries; look for endothelial cells
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Is this a resident or transient cell of the connective tissue?
Mast cell- resident
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Is this a resident or transient cell of the connective tissue?
Macrophage- transient
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These cell types are (transient/ resident) cells of connective tissue
These cell types are **transient** cells of connective tissue (**leukocytes)**
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Differentiate between connective tissue from mesenchymal stem cells vs. hematopoietic stem cells
Mesenchymal:
* condroblasts --> chondrocytes
* adipocytes
* fibroblasts
* mesothelial cells
* endothelial cells
* osteoblast --> osteocyte
Hematopoietic:
* macrophage
* osteoclast
* mast
* neutrophil
* etc
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What is the function of this cell?
**Fibroblast** product procollagen and ECM components; aid in wound healing
* Active --> spindle/ fusiform
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What role do fibroblasts play in wound healing?
**Fibroblasts** migrate across blood clots where they adhere to **fibronectin** (a glycoprotein in ground substance)
91
The following cells have what function?
**White adipose tissue**: "unilocular fat"
* Synthesis and storage (TG) of fat
* Rich neurovascular supply
* Cytoplasm and nucleus squeezed to periphery
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What gives this cell its brown color?
Mitochondria!
* UCP1: uncoupling protein 1 allows proton movement to get converted to heat instead of ATP
*Brown fat is multilobular*
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Dense regular connective tissue is found in _ areas of the body and made of _ collagen
Dense regular connective tissue is found in **tendons, ligaments** areas of the body and made of **type I** collagen
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Dense irregular connective tissue is found in _ areas of the body and made of _ collagen
Dense irregular connective tissue is found in **skin, organ capsule** areas of the body and made of **type I** collagen
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Reticular connective tissue proper is found in _ areas of the body and has _ collagen
Reticular connective tissue proper is found in **bone marrow, lymph nodes, spleen** areas of the body and has **type III** collagen
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Where do we find loose, areolar connective tissue?
Supporting tissue & lamina propria
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What is this cell's function?
**Mesenchyme**- stem cells can differentiate into fibroblasts, osteoblasts, endothelial cells, adipocytes, chondroblasts
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The endomysium and perimysium surround what?
**Endomysium**: surrounds cells (myofibers)
**Perimysium**: surrounds fasciles (bundles)
**Epimysium**: surrounds entire muscle; forms aponeuroses and tendons
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Epimysium
Perimysium
Endomysium
Muscle
Fasicle
Cell
Myofibril
Myofilament
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What would happen if we didn't have the structure marked T in some muscle fibers?
Lacking T-tubules = uncoordinated contraction of myofibrils
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What is seen in the periphery of cell 1 and cell 2? Purple
Nucleus
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Which bands shorten during muscle contraction?
H and I bands
103
What is the dark band in the middle?
A band
