Chapter 5: Histology Flashcards
1
Q
Define “tissue”
A
a group of similar cells and cell products that arise from the same region of the embryo and work together to perform a specific structural or physiological role in an organ.
2
Q
Name the 4 primary tissues types.
A
- epithelial
- connective
- nervous
- muscular
3
Q
Define “histology”
A
the study of tissues and how they are arranged into organs
4
Q
Define “extracellular matrix”
A
extracellular material (non-cellular component of tissues and organs–especially of connective tissue)
- made of fibrous proteins and a clear gel called “ground substance”
- hard matrix: cartilage and bone
- liquid matrix: blood and lymph
- fibrous matrix: (connective tissue proper) loose and dense
- ground substance contains interstitial fluid, proteins, and proteoglycans–typically refers to connective tissue
5
Q
What is the matrix?
A
Extracellular material that surrounds the cells, and the relative amount of space occupied by the cells and matrix.
6
Q
What is the matrix composed of?
A
- Fibrous proteins
- Clear gel called ground substance
7
Q
What are the four types of epithelia?
A
- Simple squamous
- Simple cuboidal
- Simple columnar
- Pseudostratified columnar
8
Q
Why is pseudostratified columnar a debatable epithelia?
A
- Falsely appears stratified
- Some cells are taller than others
- Every cell reaches the basement membrane
- Not all cells reach the free surface
9
Q
What are the functions of the integumentary system?
A
- regulation of body temperature
- (sweating, vasodilaton/constriction of blood cells)
- Protection
- against bacteria, chemicals, UV, light, abrasion, dehydration
- sensory receptors
- (touch, itch, temperature, pressure, pain, vibration)
- excretion and absorption
- pain patch, excrete waste)
- synthesis of Vitamin D
10
Q
What are the two layers of the dermis?
A
Papillary region
- finger-like projections (dermal papillae)
- Meissner’s (tacticle) corpuscles for light touch
Reticular Region
- oil glands, sweat glands, hair follicles
- lamellar / Pacinian corpuscles used for pressure (deep touch)
11
Q
What are the five distinct layers of the epidermis?
A
- stratum corneum
- flat, dead cells filled with Keratin
- stratum lucidum (thick skin ONLY)
- clear layer
- stratum granulosum
- transitim (grainy) layer
- above this layer is dead, below it is alive
- stratum spinosum
- looks “spiny” on a slide
- stratum basale
- single layer of stem cells
- melanocytes are here
12
Q
What are goblet cells?
A
Wine-glass shaped mucus-secreting cells in simple columnar and pseudostratified epithelium
13
Q
What are the functions of simple squamous epithelium?
A
- Permits rapid diffusion or transport of substances
- Secretes serous fluid
14
Q
Identify the following: hair, arrector pili muscle, sebaceous gland, sudoriferous (sweat) glands, tactile (Meissner’s) corpuscles, and lamellar (Pacinian) corpuscle
A
…..
15
Q
Skin reference sheet
A
16
Q
What is the location and function of epithelial tissue?
A
Location:
- epidermis
- inner lining of digestive tract
- liver and other glands
Function:
- protection (covers surface and lines body cavities)
- sensory input, absorption, makes up glands, filtration, and secretion
17
Q
What are the characteristics of epithelial tissue?
A
- avascular (without blood supply)
- annervated
- fit closely together
- held by “watertight junctions” and desmosomes
- has a top (apical surface) and a bottom (basement membrane; basal surface on top of it)
- may have microvilli or cilia on apical
- good regenerative powers
18
Q
What is the naming convention for epithelial tissue and what are the two exceptions?
A
- First name: number of layers, second name: shape of cells
- Exception: pseudostratified columnar epithelium (looks like baby trees growing next to tall trees–looks like many layers but is one) and transitionial epithelial tissue (bladder / ureters only)
19
Q
What is the location and function of connective tissue?
A
Location
- most abundant and widespread tissue in the body
- various types and functions
Function
- Binding of organs
- Support (bone)
- Physical protection
- Immue protection (battlefield under skin)
- Movement (bone)
- Storage (fat and bone)
- Heat production (brown fat)
- Transport (blood)
20
Q
What are the characteristics of connective tissue?
A
- derived from mesenchyme (embryonic connective tissue)
- usually vascular (has blood vessels)
- except cartilage, ligaments, and tendons–only on membrane above
- good nerve supply
- cell separated by large amount of nonliving, extracellular matrix
21
Q
What are the types of fibrous connective tissue?
A
Loose connective tissue
- more gel-like substance between cells
- areolar, reticular, and adipose
Dense connective tissue
- fibers fill spaces between cells
- dense regular connective tissue and dense irregular connective tissue
22
Q
What are the 3 types of fibers?
A
- collagenous (tough, flexible, resist stretching)
- reticular (thin, spongelike / highly branched framework)
- elastic (thinnest) (tendency to recoil when tension is released)
23
Q
Describe the structure, function, and location of the following 3 loose connective tissue: areolar, reticular, and adipose
A
Areolar
- loose mesh, all 3 fibers
- wraps and cushions organs
- between muscles, passageway for blood and nerves, under epithelia
Reticular
- highly branched, retains shape
- mainly reticular fibers
- soft internal skeleton for lymph nodes, spleen, and bone marrow
Adipose
- fat
- like areolar but sparse fibers
- provides energy, insulation, and padding
- brown feat produces heat (juvenils only)
24
Q
Describe the structure and location of the 2 dense connective tissues
A
Dense regular
- very strong
- mainly collagen, fibers run in one direction (parallel)
- tendons, ligaments
Dense Irregular
- mainly collagen, fibers run in all directions
- dermis, organ capsules
25
What is the structure and function of hyaline cartilage connective tissue?
* most abundant cartilage
* rubbery matrix
* contains chondrocytes in lacunae
* costal (ribs) cartilage
* articular cartilage
* respiratory cartilage (nose, trachea, very breakable)
26
What is the structure and function of elastic cartilage connective tissue and fibrocartilage connective tissue, respectively?
Elastic cartilage
* similar to hyaline but elastic fibers
* flexible support
* outer ear, epiglottis
Fibrocartilage
* similar to hyaline but more collagen fibers
* strongest cartilage
* made to compress, shock absorber
* interverterbal discs, pubic symphysis, discs in knee (menisci)
27
What is the structure and function of osseous connective tissue and blood as connective tissue?
Osseous tissue
* bone tissue
* flexible
* hard, calcified matrix with collagen
* osteocytes in lacunae
* support, protection
* *(work with muscles for movement, storage of fat and calcium, make blood cells)*
Blood
* RBC and WBC in fluid matrix
* cardiovascular and immue systems
* plasma--blood's ground substance
28
Photomicrograph of areolar connective tissue
29
Photomicrograph of adipose connective tissue
30
Photomicrograph of osseous connective tissue
31
Photomicrograph of blood connective tissue
32
What is meant by nervous and muscular tissues being "excitable" tissues?
they respond to stimuli by changing membrane potential
* membrane potential is electrical charge difference (voltage) that occurs across cell membrane
* in nerve cells ,changes in voltage result in rapid transmission to other cells
* in muscle cells, changes in voltage cause contraction
33
What are the 2 types of nervous tissue cells?
Neurons
* transmit electrical impulses
* a neuron will either go down a dendrite into the cell body or in axon away from cell body
Neuroglia
* support, protect, provide nutrients to neurons
34
What are the 3 types of muscle tissue and their characteristics?
Skeletal muscle
* striatied, multinucleate, voluntary
Cardiac Muscle
* striated, uninucleate, involuntary
Smooth (or visceral) muscle
* nonstriated, uninucleate, involuntary
35
What are the 2 types of fibrous connective tissues?
Loose connective tissue
* more gel-like ground substance between cells
* areolar, reticular, adipose
Dense connective tissue
* fibers fill spaces between cells
* regular/irregular
36
What are the specialized cells / membranes of connective tissue?
* fibroblasts (make fibers)
* chondroblasts (make cartilage)
* chondrocytes (cartilage cells trapped in lacunae)
* osteoblasts (make bone)
* perichondrium: membrane of dense irregular connective tissue that surrounds elastic and most hyaline cartilage (not articular) and contains reserve population of chondroblasts (to make more cartilage if needed)
37
What are the 3 types of cell junctions?
Tight junctions
* seal off intercellular space, "watertight"
* make it difficult for substances to pass between cells
* (e.g. hold urine in bladder)
desmosomes:
* keeps cell from pulling apart
* resist mechanical stress
* e.g. skin, cardiac muscle
Gap junctions
* communicating junction (for rapid communication)
* formed by ring-like connexon
* e.g. 4 regions of the heart know to contract at the same time
38
What are exocrine glands, their types, their structures, and examples?
* maintain their contact with surface of epithelium by way of a duct
* can be internal or external
* **merocrine gland**: products are secreted by exocytosis
* used by **eccrine** sweat glands (cooling)
* **suderiferous/apocrine** gland: scent sweat gland
* **apocrine**: fat droplets bud off plasma membrane
* (e.g. milk fat secretion from mammary)
* **holocrine**: products are secreted by rupture of whole gland cell
* e.g sebaceous gland (oil)
39
What are endocrine glands?
Glands that secrete hormones into the blood.
40
What are unicellular glands?
* glands found in an epithelium that is predominantly nonsecretory
* can be exocrine or endocrine
* e.g. mucus secreting goblet cells in trachea
41
What are membranes and their two types / substrates?
Membranes are thin sheets of tissue.
* Epithelial membranes
* 2 layers of epithelial tissue over connective tissue
* serosa, mucosa, and cutaneous membrane
* Connective tissue membranes
* made only of connective tissue
* synovial membranes (around every joint), meninges (brain and spine), periosteum (bone), perichondrium (cartilage)
42
Describe the strucure and function of the 3 epithelial membranes
* Mucosa
* lines cavities with connection to the outside
* produces mucus
* e.g. digestion, respiratory, urinary, reproductive
* Serous (serosa)
* lines cavities with no connection to outside
* visceral
* parietal
* produces watery serous fluid
43
What are the two forms of tissue repair?
* regeneration: replacement of dead or damaged cells by the same type of cell as before
* fibrosis: replacement of damaged cells with scar tissue (does not restore function)
44
What tissues are good / bad at repair?
* Good: epithelial, bone, areolar, dense irregular
* Moderate: dense regular, smooth muscle
* Poor: cartilage, skeletal muscle
* Almost none: cardiac muscle, neurons
45
What are the functions of epithelial tissue?
* Protection- lines cavities, surfaces of organs, skin
* Sensation- sensory input
* Secretion-produces mucus, sweat, enzymes, hormones, and most of the bodies other secretions
* Absorption- absorbs chemicals from the adjacent medium. For example, nutrients are absorbed through the epithelium of the small intestine.
* Filtration - All substances leave in the blood are selectively filtered through the epithelium that lines the blood vessels; all urinary waste is filtered through epithelia of the kidneys
* Excretion- epithelia voids waste from the tissues, such as CO2 across the pulmonary epithelium
46
What are the functions of connective tissue?
* protection
* binding and support
* insulation
* transportation
* most adundant and widespread tissue in the body
47
How many types of epithelia are there?
4
48
Where is the basement membrane layer located?
The basement membrane is located between an epithelium and the underlying connective tissue
49
What is another name for histology?
Microscopic anatomy
50
What are the two distinct regions of the integumentary system?
Skin (cutaneous membrane)
* epidermis
* dermis
Subcutaneous Layer
* hypodermis / superficial facia
* NOT a part of the skin!
51
What are some characteristics of adipose tissue?
* Brown fat of juveniles produce heat
* Empty-looking cells with thin margins; Nucleus pressed against cell membrane
* Energy storage, insulation, cushioning
* Subcutaneous fat and organ packing
52
What are names of the clear gel [ground substance] in the matrix?
* Tissue fluid
* Interstitial fluid
* Tissue gel
* Extracellular fluid (ECF)
53
How do the tissue types differ from each other?
* Types and functions of their cells
* Characteristics of the matrix (extracellular material)
* Relative amount of space occupied by cells versus matrix
54
What are some characteristics of epithelial tissue?
* Epithelia are sheets of closely adhering cells, one or more cells thick
* Avascular (does not have blood vessels)
* Covers body surfaces and lines body cavities
* Upper surface usually exposed to the environment or an internal space in the body
* Constitutes most glands
* Usually nourished by underlying connective tissue
55
What is the basal surface?
Surface of epithelial cell facing the basement membrane
56
What is the apical surface?
Surface of epithelial cell that faces away from the basement membrane
57
What are some characteristics of simple epithelia?
* Contains one layer of cells
* Named by shape of cells
* All cells touch basement membrane
58
What are some characteristics of stratified epithelia?
* Contains more than one layer
* Named by shape of apical cells
* Some cells rest on top of others and do not touch basement membrane
59
Where are simple squamous epithelium tissues found?
Alveoli, glomeruli, endothelium and serosa
60
Some functions and characteristics of simple squamous epithelium
* Single row of thin cells
* Permits rapid diffusion or transport of substances
* Secretes serous fluid
61
What are some functions and characteristics of simple cuboidal epithelium?
* Single layer of square or round cells
* Absorption and secretion, mucus production
62
Where are simple cuboidal epithelium tissues located?
* Liver
* Thyroid
* Mammary and salivary gland
* Bronchioles
* Kidney tubules
63
What are some functions and characteristics of simple columnar epithelium?
* Single row of tall, narrow cells
* Oval nuclei in basal half of cell
* Brush border of microvilli, ciliated in some organs, may possess goblet cells
* Absorption and secretion; secretion of mucus
64
Where are the locations for simple columnar epithelium tissues?
* Lining of G.I. tract
* Uterus
* Kidney
* Uterine tubes
65
What are some functions and characteristics of pseudostratified epithelium?
* Looks multilayered, but all cells touch basement membrane
* Nuclei at several layers
* Has cilia and goblet cells
* Secretes and propels mucus
66
Where are the locations of pseudostratified epithelium tissues?
* Respiratory tract
* Portions of male urethra
67
How many layers of cells are in stratified epithelia tissues?
It ranges from 2 to 20 or more layers of cells. Some cells rest directly on others.
68
What is dense irregular connective tissue and where is it located?
* Densely packed, randomly arranged, collagen fibers and few visible cells
* Withstands unpredictable stresses
**_Locations_**
Deeper layer of skin; capsules around organs
69
What are the four types of stratified epithelia?
Named for the shapes of their apical surface cells
1. Stratified squamous
2. Stratified cuboidal
3. Stratified columnar (rare)
_Fourth type_
Transitional epithelium
70
What's the most widespread epithelium in the body?
Stratified squamous
71
What are the two kinds of stratified squamous epithelium and where are they located?
1. Keratinized- found on skin surface, abrasion resistance
2. Non-keratinized- lacks surface layer of dead cells
72
What happens at the deepest layer of stratified epithelial
* Undergoes continuous mitosis
* Daughter cells push toward the surface
* Daughter cells become flatter as they migrate upward
* Finally die and flake off (exfoliation or desquamation)
73
What are some important information about keratinized stratified squamous tissues?
* Multiple cell layers; cells become flat and scaly towards surface
* Resists abrasion; prevents water loss through skin
* Resists penetration by pathogenic organisms
74
Where are the locations of keratinized stratified squamous epithelium tissue?
* Epidermis
* Palms
* Soles(heavily keratinized)
75
What are some important information about non-keratinized stratified squamous tissues?
* Same as keratinized epithelium without surface layer of dead cells
* Resists abrasion and penetration of pathogens
76
Where are the locations of non-keratinized stratified squamous epithelium?
* Tongue
* Oral mucosa
* Esophagus
* Vagina
77
What are some important information about stratified cuboidal epithelium?
* Two or more cell layers; surface cells square or round
* Secretes sweat; produces sperm, produces ovarian hormones
78
What are the locations of stratified cuboidal epithelium?
* Sweat gland ducts
* Ovarian follicles
* Seminiferous tubules
79
Important information about transitional epithelium
* Multi layered epithelium with surface cells that change from round to flat when stretched
* Allows for a filling of urinary tract
80
Where is transitional epithelium located?
Ureter and bladder
81
Definition of connective tissue?
A diverse, abundant type of tissue in which cells occupy less space than matrix
82
What are some important things about connective tissue?
* Most cells are not in direct contact with each other
* Supports, connects and protects organs
* Highly variable vascularity
83
What do the cells of fibrous connective tissue consist of and what are their functions?
* Fibroblasts produce fibers and ground substance of matrix
* Leukocytes(WBC)- neutrophils attack bacteria. Lymphocytes react against bacteria, toxins, and other foreign agents.
* Plasma cells- synthesize antibodies (proteins). They arise from lymphocytes.
* Mast cells- often found alongside blood vessels. Secrete heparin to inhibit clotting. Secrete histamine to dilute blood vessels.
* Adipocytes store triglycerides (fat molecules)
84
What does highly variable vascularity mean in connective tissues?
Loose connective tissues have many blood vessels.
Cartilage has few or no blood vessels
85
What's so special about the ground substance of extracellular matrix for connective tissues?
* Usually has a gelatinous to rubbery consistency
* Composed mainly of:
* Interstitial fluid
* Proteoglycans
* Adhesive glycoproteins
* Protein carbohydrate complexes
* Bind components of a tissue together
86
What are the two types of fibrous connective tissue, and what types do they have?
1. Loose connective tissue
* Much gel like ground substance between cells
* The two types are:
* Areolar
* Reticular
2. Dense connective tissue
* Fibers fill spaces between cells
* Types vary in fiber orientation
* Dense regular connective tissue
* Dense irregular connective tissue
87
What are the three types of protein fibers that are found in fibrous connective tissues?
1. Collagenous fibers
2. Reticular fibers
3. Elastic fibers
88
What are some functions and characteristics of _collagenous_ fibers(of the fibrous connective tissue matrix)?
* Collagen is most abundant of the body's proteins (25%)
* Tough, flexible, and stretch resistant
* Tendons, ligaments, and deep layer of the skin are mostly collagen
* Less visible in matrix of cartilage and bone
89
What are some functions and characteristics of _reticular_ fibers(of the fibrous connective tissue matrix)?
* Thin collagen fibers coated with glycoprotein
* Form framework of spleen and lymph nodes
90
What are some functions and characteristics of _elastic_ fibers(of the fibrous connective tissue matrix)?
* Thinner than collagenous fibers
* Branch and re-join each other
* Allows stretch and recoil
* Made of protein called elastin
91
Describe the _areolar_ tissue(of fibrous connective tissue)
Loosely organized fibers, abundant blood vessels and a lot of seemingly empty space
92
Describe the areolar tissue and its locations
* Loosely organized fibers, abundant blood vessels
**_Locations_**
* Underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
93
Describe _reticular_ tissue(of fibrous connective tissue) and its locations?
* Mesh of reticular fibers and fibroblasts
* Form supportive stroma (framework) for lymphatic organs
**_Locations_**
* **__**Lymph nodes, spleen, thymus and bone marrow
94
What is the meaning and the types of adipose tissue?
Fat tissues in which adipocytes are the dominant cell type
The two types of fat are white and brown
95
What is white fat?
Type of adipose tissue which is mainly found in adults
* Specimens resemble chicken wire
* Provides thermal insulation
* Cushions organs such as eyeballs, kidneys
* Contributes to body contours-- female breasts and hips
96
What is brown fat?
Adipose tissue which is found in fetuses, infants and children
* Color comes from blood vessels and mitochondrial enzymes
* Functions as a heat-generating tissue
97
Tell me about dense regular connective tissue(of fibrous connective tissue)
* Densely packed, parallel collagen fibers
* Compressed fibroblast nuclei
* Elastic tissue forms wavy sheets in some locations
* Tendons attach muscles to bones and ligaments hold bones together
98
What is cartilage?
* Stiff connective tissue with flexible matrix
* Gives shape to ear, tip of nose, and larynx
99
What are chondroblasts?
Cartilage cells that are trapped in lacunae (cavities)
100
What is perichondrium?
101
What's so special about cartilage?
* No blood vessels
* Diffusion brings nutrients and removes waste
* Heals slowly
* Matrix rich in GAGs and contains collagen fibers
102
What are some characteristics of hyaline cartilage and where is it located?
103
What is a bone?
* Also known as osseous tissue. It is a calcified connective tissue.
* Bones of the skeleton are organs made of bone tissue, cartilage, marrow, and other tissue types
104
What are the two types of osseous (bone) tissue?
1. Spongy bone- porous appearance
* Delicate sets of bone: trabeculae
* Covered by compact bone
* Found in heads of long bones and in middle of flat bones such as the sternum
2. Compact bone: denser, calcified tissue with no visible spaces
* More complex arrangement
* Cells and matrix surround vertically oriented blood vessels in long bones
105
What are erythrocytes and leukocytes?
* Erythrocytes- red blood cells that transport O2 and CO2
* Leukocytes- white blood cells defend against infection and disease
106
What are compact bones?
* Arranged in cylinders that surround central (haversian or osteonic) canals that run longitudinally through shafts of long bones
* Blood vessels and nerves travel through central canal
* Bone matrix deposited in concentric lamellae
* Onion-like layers around each central canal
107
What is blood?
Fluid connective tissue that transports cells and dissolved matter from place to place
108
What is plasma?
Blood's ground substance
109
What are formed elements?
Cells and cell fragments
110
What are platelets?
Cell fragments involved in clotting
111
What is a nervous tissue?
Specialized for communications by electrical and chemical signals
112
What are neurons and neuroglia?
* Neurons (Nerve cells)
* Detect stimuli
* Respond quickly
* Transmit information rapidly to other cells
* Neuroglia (glial)
* Protect and assist neurons
* “Housekeepers” of nervous system
* More numerous than neurons
113
What are the parts and function of the **_neuron_**(of nervous tissue)?
* Dendrites
* Multiple short, branched processes
* Receive signals from other cells
* Transmit messages to neurosoma
* Neurosoma (cell body)
* Houses nucleus and other organelles
* Controls protein synthesis
* Axon (nerve fiber)
* Sends outgoing signals to other cells
* Can be more than a meter long
114
What is muscular tissue?
Elongated cells that are specialized to contract in response to stimulation
115
What is the primary job of muscular tissue?
116
What are the functions of muscle tissue?
* Creates movements involved in body and limb movement, digestion, waste elimination, breathing, speech, and blood circulation
* Important source of body heat
117
What are the three types of muscle tissue?
1. skeletal
2. cardiac
3. smooth
118
Tell me some things about skeletal muscle
* Made of muscle fibers—long thin cells
* Most skeletal muscles attach to bone
* Contains multiple nuclei adjacent to plasma membrane
* Striations—alternating dark and light bands
* Voluntary—conscious control over skeletal muscles
119
What do I need to know about cardiac muscle?
* Limited to the heart
* Cardiomyocytes are branched, shorter than skeletal muscle fibers
* Contain one centrally located nucleus
* Intercalated discs join cardiomyocytes end to end
* Provide electrical and mechanical connection
* Striated and involuntary (not under conscious control)
120
What do I need to know about smooth muscle tissue?
* Made of fusiform myocytes lacking striations
* Cells are relatively short and have one central nucleus
* Involuntary function
* Most is visceral muscle—making up parts of walls of hollow organs
121
Name the 10 types of connective tissues?
1. Areolar Tissue
2. Reticular Tissue
3. Dense Regular Connective Tissue
4. Dense Irregular Connective Tissue
5. Adipose Tissue
6. Hyaline Cartilage
7. Elastic Cartilage
8. Fibrocartilage
9. Bone
10. Blood
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