Lab 1: Histology and Integumentary System Flashcards
1
Q
define histology
A
the study of tissues
2
Q
define tissues
A
a group a similarly structured cells that work together to accomplish a specific function
3
Q
what are the four major tissue categories
A
- epithelial
- connective
- muscle
- nervous
4
Q
how are specimens for histology prepared
A
- fixed/preserved
- thinly sectioned
- stained to improve contrast
5
Q
what is the difference between acid stains and basic stains
A
- acid stains have negatively charged dyes
- basic stains have positively charged dyes
6
Q
what do dyes bind to
A
oppositely charged macromolecules
7
Q
define artifact
A
- a minor distortion in sectioned tissues that is only present due to the many steps needed to produce a histology slide
- should not be confused with the actual structure of preserved tissue
8
Q
what does epithelial tissue do
A
- lines and covers organs, as well as their internal passageways
- creates boundaries between different environments
- forms glands
9
Q
what are the strong intercellular connections between epithelial cells formed by
A
- tight junctions
- desmosomes
10
Q
describe tight junctions
A
- connections between adjacent cells
- prevents fluid from moving between the cells
11
Q
describe desmosomes
A
- connections between adjacent cells
- contains proteins
- allows cells to mechanically hold on to each other, providing mutual reinforcement
12
Q
what are the functions of epithelia
A
- filtration
- absorption
- protection
- secretion
- excretion
- sensory reception
13
Q
define the free/apical surface of epithelium
A
surface where cells are exposed to external environment or internal passageway/cavity
14
Q
how do cells on the free/apical surface of epithelium obtain nutrients
A
diffusion of substances from connective tissue underlying the epithelia
15
Q
define the basal lamina of epithelium
A
- where epithelium is attached to the body
- located between the epithelium and the connective tissue layer
16
Q
what is the composition of basal lamina of epithilium
A
- glycoprotein secretions from the epithelial cells
- collagen fibers
17
Q
what is the function of the basal lamina
A
- filter at the base of the epithelium
- forms a scaffold for wound repair
18
Q
how are epithelia named
A
- shape
- number of cell layers
19
Q
define simple epithelium
A
epithelium with only one layer of epithelial cells
20
Q
what are the functions of simple epithelia
A
- diffusion
- absorption
- filtration
- secretion
21
Q
what is the function of goblet cells
A
protect epithelia at the free surface by secreting mucus that coats the cell
22
Q
describe the two different attachments on epithelial cells on the apical surface
A
- microvilli: increase surface area for absorption
- cilia: motile hair-like projections that sweep substances across the apical surface
23
Q
define stratified epithelia
A
epithelium with more than one layer of epithelial cells
24
Q
where is stratified epithelia found
A
- areas exposed to abrasion and friction
- body surface, upper digestive tract
25
what is the main function of stratified epithelia
protection
26
when stratified epithelium contains more than one type/shape of epithelial cell, how do you determine the classification of the tissue
the type of epithelial cell at the free surface determines the classification of the tissue
27
describe how stratified epithelia regenerates
regenerates from basal cells that divide and then move out to replace older cells near the apical border
28
what is the most common stratified epithelium
stratified squamous epithelium
29
what happens to cells on the apical surface of stratified epithelium and why
they often atrophy and flatten because they are furthest from the blood supply
30
how many layers thick is stratified cuboidal epithelium typically
two cells thick
31
where is stratified cuboidal epithelium found
- ducts of sweat glands
- mammary glands
32
where is stratified columnar epithelium found
- parts of the male urethra
- the pharynx
- lining of some glandular ducts
33
describe a squamous-shaped cell
- flattened shape
- nucleus appears flattened
34
describe a cuboidal-shaped cell
- cube shaped
- round nucleus
35
describe a columnar-shaped cell
- rectangle shaped, like a column
- oblong or round nucleus
36
what are the 6 characteristics that distinguish epithelial tissue from other tissue types
- regeneration
- polarity
- cellularity and specialized contacts
- supported by connective tissue
- avascularity
- innervated
37
why is cellular regeneration important for epithelial cells
many epithelia are subjected to friction or exposed to hostile/caustic substances
38
describe the concept of polarity in epithelial tissue
- there are differences in structure and function between the apical and basal surface of epithelia
- apical surfaces also differ: microvilli, smooth, cilia
39
describe a brush border
- microvilli on the apical surface of epithelial tissue are so dense they appear fuzzy
- often seen in secretory or absorbing tissues
40
how are epithelial cells attached to connective tissue
basement membrane
41
describe the basement membrane
- attaches epithelial tissue to connective tissue
- helps epithelia resist tearing and stretching
- reinforces structural integrity
- creates a boundary
- made up of basal lamina and reticular lamina
42
describe reticular lamina
- made of collagen fibers
- secreted by connective tissue
- part of the basement membrane
43
describe the significance of the basement membrane in cancer
cancers of the epithelial tissue cannot become metastatic until they develop a mechanism to break through the basement membrane
44
what is the only type of epithelia that is vascular
glandular epithelial tissue
45
define innervated
supplied by nerve fibers for regulation
46
what tissue has the highest regeneration capacity and what has the lowest
- highest regeneration: epithelial tissue
- lowest regeneration: nervous tissue
47
describe simple squamous epithelium
- thin and often permeable
- single layer of flattened cells with disc shaped nuclei and sparse cytoplasm
48
what is the function of simple squamous epithelium
- filtration and diffusion
- not protective
- secretes lubricating substances in serosae (tissue lining of a body cavity or outer lining of an organ)
49
locations of simple squamous epithelia
- kidney glomeruli
- air sacs of lungs
- lining of heart, blood vessels, and lymphatic vessels
- lining of ventral body cavity
50
what are the two specific types of simple squamous epithelia
- endothelium
- mesothelium
51
describe endothelium
- simple squamous epithelia
- provides slick and friction-reducing lining in hollow organs that transmit body fluids (lymph, blood)
52
describe mesothelium
- simple squamous epithelia
- found in serous membranes lining the ventral body cavity and covering its organs
53
describe simple cuboidal epithelium
- single layer of cube-like cells
- large, spherical central nuclei
54
what is the function of simple cuboidal epithelium
secretion and absorption
55
locations of simple cuboidal epithelium
- kidney tubules
- ducts and secretory portions of small glands
- ovary surface
56
describe simple columnar epithelium
- single layer of tall cells
- round to oval nuclei
- some cells have cilia
- layer may contain mucus-secreting unicellular glands (goblet cells)
57
function of simple columnar epithelium
- absorption
- secretion of mucus, enzymes, and other substances
- ciliated type propels mucus or reproductive cells by ciliary action
58
locations of simple columnar epithelium
- non-ciliated type lines most of the digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands
- ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus
59
describe keratinized epithelial cells
cells manufacture the protein keratin which toughens the cells as they die creating a dry protective barrier against abrasion, chemical exposure, and friction
60
describe stratified squamous epitheium
- thick membrane composed of several layers
- basal cells are cuboidal or columnar and metabolically active white surface cells are squamous
- surface cells in the keratinized type are full of keratin and dead
61
function of stratified squamous epithelium
protect underlying tissues in areas subjected to abrasion
62
locations of stratified squamous epithelium
- keratinized: epidermis of the skin
- non-keratinized: moist linings of the esophagus, mouth, and vagina
63
describe pseudostratified ciliated columnar epithelium
- single layer of cells of differing heights
- some cells don't reach the free surface, but all cells touch the basal lamina
- nuclei seen at different levels
- may contain mucus-secreting cells (goblet cells)
- may bear cilia
64
function of pseudostratified ciliated columnar epithelium
- secretion, particularly of mucus
- propulsion of mucus by ciliary action
65
locations of pseudostratified ciliated columnar epithelium
- non-ciliated: male's sperm-carrying ducts and ducts of large glands
- ciliated: lining nasal cavity, trachea, and bronchi
66
describe transitional epithelium
- resembles both stratified squamous and stratified cuboidal
- basal cells are cuboidal or columnar, surface cells dome-shaped or squamous-like
- not all cells touch the basal lamina
67
function of transitional epithelium
stretches readily and permits distension of certain hollow organs
68
locations of transitional epithelium
- organs that must stretch and shrink
- lines uterus, urinary bladder, and part of the urethra
69
what are the main functions of connective tissue
- provides the body with structural support and means of joining structural components to one another
- protection
- storing energy reserves
- insulating the body
- transporting substances throughout the body
70
what creates all connective tissues
mesenchyme, an embryonic tissue
71
describe the general composition of connective tissue
- mostly non-cellular
- cells sparsely spread throughout extracellular matrix
72
describe the general composition of the extracellular matrix in connective tissue
protein fibers and a ground substance secreted by cells in connective tissue
73
describe collagen fibers in the ground substance of the extracellular matrix of connective tissue
- strongest of the fibers
- made of the protein collagen
- made of many cross-linked fibrils
74
describe elastic fibers in the ground substance of the extracellular matrix of connective tissue
- made of the protein elastin
- forms in branching network int he extracellular matrix to provide strength and recoil
75
describe reticular fibers in the ground substance of the extracellular matrix of connective tissue
- short and fine
- made of the protein collagen
- form fuzzy nets with more give than that of collagen fibers
- less secreted as we age, leading to brittle bones and wrinkly skin
76
what are the three groups of connective tissue
- connective tissue proper
- fluid connective tissue
- supporting connective tissue
77
describe general characteristics of connective tissue proper
- thick liquid matrix
- variety of cell types
- divided into two groups: loose and dense
78
what do fibroblasts do in connective tissue proper
stationary cells that secrete proteins to form fibers
79
what do macrophages do in connective tissue proper
- patrol tissues and are mobilized during an infection or injury
- migrate to the site of the disturbance and phagocytize damaged tissue cells and microbes
80
what do mast cells do in connective tissue proper
- detect foreign microorganisms and initiate immune response
- release histamine that causes inflammatory response
- secrete enzymes such as heparin and proteases
81
what do adipocytes do in connective tissue proper
fat cells containing vacuoles for lipid storage
82
what are the three groups of loose connective tissues
- areolar
- adipose
- reticular
83
what are the two types of fibers that make up dense connective tissue
- protein fibers assembled into thick bundles of collagen
- elastic fibers with widely scattered cells
84
what are the two types of dense connective tissue
- dense regular
- dense irregular
85
describe the fiber arrangement in dense regular vs irregular connective tissue
- regular: protein fibers arranged in parallel bands
- irregular: fibers interwoven running in many directions
86
where is dense irregular connective tissue found
- where tension is exerted from many different directions
- capsules of some organs and joints
- dermis of the skin
- submucosa of digestive tract
87
describe the two types of fluid connective tissue
- blood: erythrocytes and leukocytes
- lymph
88
what are the two types of supporting connective tissue
- bone
- cartilage
89
what is the solid matrix of bone composed of
calcium phosphate salt, aka hydroxyapatite
90
what are the general functions of bone
- support and protect the body
- provides cavities for synthesis of blood cells and storing fat
91
why is bone more rigid than cartilage
bone has more collagen fibers and a matrix filled with hydroxyapatite
92
which is highly vascularized and innervated: bone or cartilage
bone
93
describe cartilage
- rubbery
- avascular
- non-innervated
- gelatinous matrix
- fibers for structural support
- can withstand both compression and tension because it is tough but flexible
94
define perichondrium
- membrane surrounding all supporting connective tissue in cartilage
- produces chondroblasts
95
what do chondroblasts do
- secrete fibers and the ground substance of cartilage matrix
96
how does cartilage receive nutrients
diffusion from the perichondrium
97
describe how chondroblasts become chondrocytes
- chondroblasts are produced by the perichondrium
- chondroblasts become trapped in small spaces of the matrix called lacunae
- then become chondrocytes that maintain mature tissue
98
what are the three types of cartilage
- hyaline
- elastic
- fibrocartilage
99
describe areolar tissue
- loose connective tissue
- gel-like matrix with all three fiber types
- flexible
- includes fibroblasts, macrophages, mast cells, and some white blood cells
- collagen and elastic fibers are clearly visible in the matrix
100
functions of areolar tissue
- fills spaces between structures for support and protection
- wraps and cushions organs
- macrophages phagocytize bacteria
- mast cells cause inflammation
- holds and conveys tissue fluid
101
locations of areolar tissue
widely distributed under the skin
102
describe adipose tissue
- loose connective tissue
- similar matrix to areolar tissue
- closely packed adipocytes
- nucleus pushed to the side by large fat vacuole
103
functions of adipose tissue
- reserve food fuel
- insulates against heat loss
- supports and protects organs
104
locations of adipose tissue
- under the skin in subcutaneous tissue
- around kidneys and eyeballs
- within abdomen
- in breasts
105
describe reticular tissue
- loose connective tissue
- forms internal supporting framework for soft organs
- composed of network of reticular fibers interspersed with reticulocytes
106
functions of reticular tissue
fibers form soft internal skeleton that supports other cell types including white blood cells, mast cells, and macrophages
107
locations of reticular tissue
lymphoid organs (lymph nodes, bone marrow, spleen)
108
describe dense regular connective tissue
- consists mostly of collagen with some elastic fibers organized into parallel thick bands
- fibroblasts widely interspersed
- poorly vascularized
109
functions of dense regular connective tissue
- attaches muscles to bones or muscles
- attaches bone to bone
- withstands great tensile stress when pulling force is applied in one direction
110
locations of dense regular connective tissue
- tendons
- most ligaments
- aponeuroses
111
define fascia
- flat layers of dense regular connective tissue
- protect and isolate muscles from surrounding structures and allow muscle movement
112
describe dense regular elastic tissue
dense regular connective tissue with high proportion of elastic fibers
113
functions of dense regular elastic tissue
- allows recoil of tissue following stretching
- maintains pulsatile flow of blood throw arteries
- aids passive recoil of lungs following respiration
114
locations of dense regular elastic tissue
- walls of large arteries
- ligaments associated with the vertebral column
- walls of bronchial tubes
115
describe blood
composed mostly of formed elements (erythrocytes, leukocytes, thrombocytes) suspended in plasma
116
functions of blood
transport of respiratory gases, nutrients, wastes, and other substances
117
location of blood
contained within blood vessels
118
what are the specific functions of the three formed elements in blood
- erythrocytes: transport blood gases
- leukocytes: protect the body from infection
- thrombocytes: form a plug to reduce bleeding
119
what is the most common cartilage in the body
hyaline cartilage
120
what makes hyaline cartilage different from other cartilages
- the apparent lack of fibers in the matrix
- there are elastic and collagen fibers but they do not stain
121
describe hyaline cartilage
- amorphous but firm matrix
- collagen fibers form imperceptible network
- chondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae
122
function of hyaline cartilage
- springy absorption of compression at joints
- supports and reinforces
- resilient cushioning properties
- resists compressive stress
123
location of hyaline cartilage
- embryonic skeleton
- ends of long bones in joint cavities
- costal cartilages of the ribs
- cartilages of the nose, trachea, and larynx
124
describe elastic cartilage
- similar to hyaline cartilage
- more elastic fibers in matrix that are visible
125
function of elastic cartilage
maintains shape of a structure while allowing great flexibility
126
location of elastic cartilage
- supports external ear (pinna)
- epiglottis
127
describe fibrocartilage
- matrix similar but less firm than that in hyaline cartilage
- thick collagen fibers predominate and visible
128
function of fibrocartilage
- tensile strength
- cushions joints by absorbing compressive shock
- limits bone movement
129
location of fibrocartilage
- intervertebral discs
- pubis symphysis
- discs of knee joint
130
describe skeletal muscle tissue
- composed of long cells called muscle fibers which are composed of myoblasts
- multinucleate cells
- striated due to organization of intercontractile proteins called myofilaments (actin and myosin)
131
function of skeletal muscle tissue
- voluntary movement
- locomotion
- manipulation in the environment
- facial expressions
132
location of skeletal muscle tissue
- in skeletal muscles attached to bones
- occasionally in muscles attached to skin
133
describe cardiac muscle tissue
- branching
- striated
- uninucleate cells
- cells connect at specialized junctions called intercalated discs which are desmosome rich
134
function of cardiac muscle tissue
- involuntary movement
- propels blood into circulation as it contracts
135
location of cardiac muscle tissue
the walls of the heart
136
describe smooth muscle tissue
- spindle-shaped cells with central nuclei
- no striations
- cells arranged closely to form sheets
137
function of smooth muscle tissue
- involuntary movement
- propels substances or objects along internal passageways
138
location of smooth muscle tissue
mostly in the walls of hollow organs
139
what are the two types of cells that make up the nervous system
- neurons
- glial cells
140
define nerve/neural tissue
collective of neurons and glial cells
141
describe the distinct regions of a typical neuron
- central nucleus surrounded by the cell body/soma that contains most of the organelles
- dendrites radiate out from the soma and receive signals from other cells which they send to the soma
- axon connects to the soma and sends signals to other cells
142
describe nervous tissue
- neurons are branching cells
- cell processes can be long
- other non-irritable supporting cells around the neuron
143
function of nervous tissue
transmit electrical signals from sensory receptors and to effectors (muscles and glands)
144
location of nervous tissue
- brain
- spinal cord
- nerves
145
define periosteum
- membrane surrounding bone supporting tissue
- contains osteoblasts for bone growth and repair
146
describe the function of osteoblasts
- bone growth and repair
- secrete organic components of the matrix
- become osteocytes when in the lacunae
147
what is the bulk of compact bone composed of
repeating structural units called osteons
148
what are osteons composed of
rings of concentric lamellae surrounding a central (haversian) canal that contains blood vessels and nerves
149
define canaliculi
- small channels in the lamellae that provide passageways through the solid matrix for diffusion of nutrients and wastes with the blood
- radiate from the central canal of the osteon
150
what are the main functions of bones
- provide structural support for the body
- provide point of attachment to skeletal muscles
- protect internal organs
151
what cells help calcium in bones to be stored and released as needed
- osteoblasts: constantly resynthesizing bone
- osteoclasts: constantly reabsorbing bone
152
what are the two ways that bone ossifies
- intramembranous bone
- endochondral bone
153
which bones are intramembranous bones
- cranial bones
- the clavicle
154
what do intramembranous bones develop from
fibrous membranes and endochondral bone
155
what does endochondral bone develop from
hyaline cartilage
156
describe the purpose and location of a Volkmann's canal/perforating canal
- carries nerves, blood vessels, and lymphatic vessels from the periosteum
- perpendicular to the osteon
- connects with the central/Haversian canal
157
what is the difference between concentric lamellae and interstitial lamellae
- concentric lamellae makes up each osteon
- interstitial lamellae fills the space between osteons
158
what is included in the integumentary system
- the skin
- sweat and oil glands
- hair
- nails
159
what's the largest organ in the body
the skin
160
what are the functions of the integumentary system
- protective barrier that is flexible but resistant to everyday abrasions and indiscriminate water loss
- regulates body temperature
- houses sensory receptors
- ensures water homeostasis
- protects the body from the environment
- manufactures vitamin D3
161
what are the two main tissue layers of the integument
- superficial and avascular epidermis
- deep and vascularized dermis
162
what type of tissue does the epidermis consist of
keratinized stratified squamous epithelium
163
what cell type are most cells in the epidermis
keratinocytes that produce keratin
164
where are keratinocytes produced
produced by the basal layer of the epidermis and migrate out
165
what is the lifespan of a keratinocyte
25-45 days
166
what determines whether skin is thick or thin
the thickness of the epidermis
167
what are the five layers of the epidermis starting from the apical layer
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
168
describe the stratum corneum
- horny layer
- most superficial layer of epidermis
- 20-30 layers of dead squamous anucleate cells
- 2/3 of epidermis thickness
- contains keratin
169
what are the functions of the stratum corneum
- keratin and thick plasma membranes protects the skin against abrasions
- glycolipids between cells waterproofs skin
170
describe the stratum lucidem
- clear layer
- just deep to the stratum corneum layer of the epidermis
- thin and transparent layer of cells
- found in thick skin areas (palm of hand, sole of feet)
171
what is the function of the stratum lucidem
protect the underlying strata in areas subject to abrasion
172
describe tonofilaments including their location
- parallel arrays of filaments created when keratohyalin granules cling to the keratin filaments within the dying cells
- located in the stratum corneum and stratum lucidem of the epidermis
173
describe the stratum granulosum
- granular layer
- deep to the stratum corneum (or stratum lucidem if present)
- 4 to 6 layers of darks cells that synthesize keratohyaline and lamellar granules
- where keratinization occurs
174
what is the purpose of lamellar granules in the stratum granulosum
- released into the extracellular space
- contain a water-resistant glycolipid
175
what is the purpose of keratinization in the stratum granulosum
- increase durability
- reduce water loss from the integument
176
describe the stratum spinosum
- prickly layer
- deep to the strum granulosum in the epidermis
- 5 to 7 cells that form cell attachments via desmosomes
- keratinocytes in this layer appear to have spines (prickly appearance) but this is an artifact of preparation of cells
- melanin granules and dendritic cells
177
why do keratinocytes in the stratum spinosum appear to have spines or a prickly appearance
artifact of preparation of cells
178
describe the stratum basale
- basal layer
- deepest epidermal layer
- attached to the dermis
- single layer of stem cells constantly undergoing mitosis
- melanocytes producing melanin
179
what happens to the daughter cells produced by mitosis in the stratum basale of the epidermis
- one daughter cell is pushed into the stratum spinosum
- other daughter cell stays in the stratum basale
180
describe what melanocytes and melanin do (life cycle of melanin)
- found in the stratum basale of the epidermis
- produce the pigment melanin which is packaged into melanosomes and secreted from the tips of the melanocyte
- melanin is taken up by keratinocytes and sits on the superficial sun exposed side of the nucleus to protect DNA from sun exposure
181
describe the dermis
- layer of irregularly arranged flexible and strong connective tissue
- supports and nourishes the epidermis
- supply of nerve fibers, blood vessels, and lymphatic vessels
182
what are the two layers of the dermis
- papillary layer
- reticular layer
183
describe the papillary layer
- superficial layer of the dermis
- consists of areolar tissue that contains collagen and elastic fibers
- folds called dermal papillae
- houses phagocytes
184
describe dermal papillae
- folds in the papillary layer of the dermis
- form dermal ridges that make fingerprints
- often contain Meissner's corpuscles, free nerve endings, or capillary loops
185
describe Meissner's corpuscles
- found in the dermal papillae of the papillary layer of the dermis
- touch receptors
186
describe the reticular layer
- deep layer of the dermis
- thick layer containing thick collagen fibers in dense irregular connective tissue
- pockets of adipose cells
- where hair follicles and glands originate
187
what lays between the dermis and hypodermis
cutaneous plexus of blood vessels
188
what is excreted in sweat
- water
- small amounts of sodium chloride, ammonia, urea, and uric acid
189
define exteroceptors
- found in the skin
- respond to stimuli from outside the body
190
what are the three major types of hair found in humans
- terminal
- vellus
- intermediate
191
define terminal hairs
- thick, coarse, heavy, dark
- on the scalp, eyebrows, and eyelashes
192
define vellus hairs
- lightly pigmented
- distributed over much of the skin as fine peach fuzz
193
define intermediate hairs
the hair on the arms and legs
194
what is the deepest part of the hair root called
hair bulb
195
what is contained in the hair papilla within the hair bulb
- nerves
- blood vessels
- the beginning of the hair matrix
196
define hair matrix
the living and proliferative part of the hair
197
what is the hair follicle wall (not the hair shaft) made of
- outermost peripheral connective tissue sheath
- a glassy membrane of thickened basal lamina
- innermost epithelial root sheath (divided into thick and thin layers)
198
what are the three parts of the hair shaft
- outermost cuticle containing a single layer of overlapping cells to separate adjacent cells so the hairs do not mat and hard keratin
- outer cortex containing flattened cells filled with hard keratin
- inner medulla containing soft keratin and big cells
199
describe what shape of the hair shaft will make hair kinky, wavy, and straight
- kinky: flat hair shaft
- wavy: oval hair shaft
- straight: round
200
when is the hair medulla absent
in fine hairs
201
what extra pigment is in red hair
pheomelanin
202
describe the arrector pili muscle
- smooth muscle
- attached to each hair follicle
- contract when cold or experiencing heightened emotional state (goose bumps)
- move sebum from hair follicles to skin surface for lubrication when they contract
203
describe exocrine glands
- secrete substances onto a body surface or into a body cavity
- do not release hormones into the circulation
- produce saliva, oil, sweat, mucus, bile, digestive enzymes from the pancreas
204
how to unicellular and multicellular exocrine glands differ
- unicellular: release secretions by exocytosis directly onto the epithelial surface
- multicellular: secretion passes through a duct on its way to the surface
205
what are the three types of exocrine gland cells
- merocrine
- apocrine
- holocrine
206
describe merocrine cells/glands
- in exocrine glands
- secretions exerted via exocytosis from secretory cells onto an epithelial-walled ducts or ducts then onto body surface
- ex: salivary gland
207
describe apocrine cells/glands
- in exocrine glands
- secretions bud off through the plasma membrane producing membrane-bound vesicles in the lumen
- ex: mammary gland
208
describe holocrine cells/glands
- in exocrine glands
- secretions produced in the cytoplasm of the cell and released by the rupture of the plasma membrane
- destroys the cell and results in secretion of the product into the lumen
- ex: sebaceous gland
209
describe apocrine sweat glands
- larger and in less locations (axillary and public) than eccrine sweat glands
- activated by sex steroids during puberty
- contain lipids and proteins not found in eccrine sweat glands, may contain pheromones
210
describe eccrine sweat glands
- smaller and in more locations than apocrine sweat glands
- exist throughout the dermis
- stop bacterial growth by creating the acid mantle
- vital for thermoregulation
