Unit 1 Flashcards
1
Q
metabolism
A
chemical reactions that maintain life
2
Q
catabolism
A
break down molecules to extract energy
3
Q
anabolism
A
synthesize building blocks for new molecules
4
Q
glycogen
A
polymer of glucose molecules linked together
- stored in liver and skeletal muscle
5
Q
glucose
A
fuels ATP production, has 6 carbons, broken down form of glycogen
6
Q
photosynthesis
A
plants use light energy to produce carbs from co2 and water
7
Q
how do we get energy from glucose
A
use energy from carbon-carbon bonds in glucose to convert it to ATP
ADP+energy+energy from food = ATP
8
Q
what is glucose ultimately broken down into
A
CO2, water, high energy electrons
9
Q
What are the electron carriers
A
NAD+ and FADH, transport hight energy electrons for ATP synthesis, derived from vitamins
10
Q
how are high energy electrons used
A
used to link P to ADP to make ATP
11
Q
where do energy-depleted electrons go
A
picked up by oxygen to form water
12
Q
what does each oxidized glucose molecule make
A
CO2, H2O, ATP
13
Q
where does glycolysis happen
A
in the cytoplasm
14
Q
what parts of energy production happen in the mitochondria
A
pyruvate to acetyl CoA, citric acid cycle, ETC
15
Q
process of glycolysis
A
glucose splitting: 1 six-carbon glucose molecule into 2 three-carbon pyruvate molecules
invests 2 ATP, get 4 ATP and high energy molecules
16
Q
Anaerobic process to pyruvate
A
converted to lactate, lactate converted back to pyruvate, back to glucose with ATP in the liver
17
Q
Aerobic process to pyruvate
A
pyruvate converted to Acetyl CoA,
- one carbon lost to CO2
- remaining two linked to coenzyme A to form acetyl CoA
- 2 pyruvate produces 2 acetyl CoA
18
Q
is the acetyl CoA process reversible?
A
no, enters citric acid cycle next
19
Q
What is coenzyme A
A
vitamin derivative, links with two carbons to form acetyl CoA
20
Q
Citric Acid Cycle / Krebs Cycle first step
A
first reaction uses oxaloacetate, regenerated in last cycle
21
Q
oxaloacetate process in krebs cycle
A
oxaloacetate combines with acetyl CoA which releases coenzyme A and forms citrate.
two carbos attached to acetyl CoA release to form CO2
22
Q
what do reactions of the citric acid cycle produce
A
one guanosine triphosphate (GTP), transfer pairs of high energy electrons to 3 molecules of NAD+ and FADH, oxaloacetate regenerated (per acetyl CoA)
23
Q
guanosine triphosphate
A
similar to ATP, structurally considered as 1 ATP produced
24
Q
how many times does the citric acid cycle happen for one glucose molecule
A
twice, one time for each of the acetyl CoA produced by a glucose molecule
25
Electron Transport Chain
high-energy electrons carried to chain by NADH and FADH2, as electrons travel along ETC (4 protein complexes), give up energy to power the production of ATP (ADP + Pi)
26
where is the ETC located
inner membrane of the two membranes of the mitochondria
27
ATP synthase
enzyme at end of ETC, starts rotating as hydrogen ions flow down against a concentration gradient, which generates ATP
28
how do energy levels chain as electrons move down the ETC
from a higher energy level to a lower energy level as they are passed down the chain between the 4 protein complexes
29
what does the ETC produce
~ 25 ATP and H2O
30
how is energy gained from fat
3 fatty acids + glycerol (glycerol backbone broken off by lipase enzyme)
beta oxidation - takes place in mitochondria, enzyme clips 2-carbon chains off of link to form Acetyl CoA
31
carnitine
transports fatty acids across mitochondrial membrane to be broken down into energy
32
energy from proteins
used only in starvation, amino acids stripped away to produce carbon skeleton
33
describe an oxygen atom
pair of electrons in first shell, 6 in second shell (8 to be stable)
34
describe a hydrogen atom
single electron
35
covalent bond
bond that shared electrons
36
dipole moment
determined by the magnitude of charges of the molecule and the distance between them
37
hydrogen bond
electrostatic attraction between hydrogen in atom in one polar molecule and a small electronegative atom
38
how are hydrogen bonds arranged in a solid
organized manner, open crystalline structure
39
describe surface tension
forces act on surface to minimize overall surface area, molecules pulled in all directions underwater, only sideward and downward on surface
40
hydrophilic
water loving (charged and polar molecules)
41
hydrophobic
water fearing (uncharged and nonpolar molecules)
42
diffusion
random movement of water molecules, diffuses ions from high concentration to lower concentration until equilibrium
43
equilibrium
probability of molecule moving right to left is the same as left to right
44
osmosis
water moves from higher concentration to lower concentration across selectively permeable membrane
45
hydrostatic pressure
weight of pressure on a solution
46
Ampithaic molecule
hydrophobic and hydrophilic properties
47
phospholipid structure
hydrophilic head, hydrophobic tail
48
phospholipid bylayer
30000 phospholipids surround a cell, 0.012 degree of curvature between adjacent phospholipid
49
lipid mosaic model
proteins embedded in lipid bylayer
50
glycosylation
addition of sugars to proteins, affects bio processes such as protein-ligand interactions, protein stability
51
Central Dogma
by james watson and francis crick, theory how info from DNA is copied to RNA
52
order of DNA to Protein
DNA > transcription > RNA > Translation > Protein
53
primary protein structure
Single chain of linked amino acids
54
what bonds links amino acids
peptide bonds
55
Secondary protein structure
local folding of polypeptide chain to alpha helices or beta sheets, formed by hydrogen bonds from backbone
56
Tertiary protein structure
3 dimension folding pattern of protein due to side-chain interactions
57
Quaternary protein structure
protein consisting of more than one amino acid chain
58
What are the structural components of an amino acid
Amino group, alpha carbon group, carboxyl group, R group (varies by AA)
59
How are the peptide bonds between amino acids formed
covalent bond, carbon on carboxyl group forms covalent bond with nitrogen in the amine group
60
Alpha helices structure
polypeptide back bone forms compact corkscrew, connected by I+4h bonding
61
i + 4H bonding
each peptide bond c = o is bound to the N - H four amino acid residues ahead of it, forms corkscrew shape in alpha helices
62
beta-sheet protein structure
more extended, hydrogen bonds are formed between the peptide bond C=O and N-H groups of polypeptides that lie side by side
63
Where are proteins found
receptors, hormones, enzymes, transport proteins, antibodies
64
what determines shape of proteins
type of amino acids, order of amino acids, bonds between amino acids, environmental factors (temp, pH)
65
Prions
protein infectious agents - abnormally shaped proteins capable of interacting with other proteins
66
Respiratory Quotient
a number which indicates which nutrient is used by the body to generate ATP
- CO2 exhaled divided by volume of O2 used
67
What are the RQ numbers for the three common microfibers
Carb: 1
Protein: 0.8
Fat: 0.7
68
what is the resting RQ value
0.8, because average of carbs and fats being used
69
what is the creatine phosphate value
0.8
70
what is the anaerobic RQ value
1
71
What is the RQ value for aerobic values
1 - 0.7
72
How does creatine work
creatine phosphate gives up phosphate to make ATP
- made from amino acids (glycine)
- synthesized in liver, stored in muscle (94%), excreted as creatinine
73
how does creatinine relate to muscle mass
more muscle = more creatine
74
describe the nucleus
- contains DNA
- membrane continuous with ER
- pores in nuclear membrane open to cytosol, allowing selective transport
75
how is DNA organized
DNA wound around histones (proteins),
nucleosomes (complex of DNA and proteins) > Chromatin > Chromosomes
76
Euchromatin
loose form of DNA, accessible for translation
77
Heterochromatin
compact form of DNA, inaccessible for translation
78
Nucleotide
base, sugar, and phosphate group
79
Nucleoside
base, sugar
80
nitrogenous bases
adenine, guanine, cytosine, thymine
81
purines
adenine and guanine (double-ring structure)
82
pyrimidines
cytosine, thymine (single benzene ring)
83
difference between thymine and uracil
thymine has an extra methyl group than uracil
84
pentose sugar in DNA and RNA carbon 1
links the base
85
pentose sugar in DNA and RNA carbon 2
identifies ribose or deoxyribose sugar
86
pentose sugar in DNA and RNA carbon 3 and 5
forms phosphodiester bond which links each nucleotide to each other
87
How do phosphodiester bonds work
OH on 3' carbon of first nucleotide binds phosphate group of 5' carbon on second nucleotide
- inorganic pyrophosphate (ppi) leaves
88
what type of bonds form the nucleic acid backbone
phosphodiester bonds
89
nucleic acid polymer nomenclature
name bases starting from 5' end (first nucleotide) to 3' end (last nucleotide)
90
antiparallel orientation
strands of DNA run in opposite directions
91
how are base pairs of DNA held together
hydrogen bonds
92
how many hydrogen bonds hold adenine and thymine together
2
93
how many hydrogen bonds hold cytosine and guanine
3
94
what is the rationale for base pairing
the optimal distance between H bonds
- 2 purines will not fit
- 2 pyrimidines will be far apart
- electrostatic attraction won't work between others
95
Helicase
breaks H-bonds between base pairs
96
DNA primase
creates RNA primer for DNA polymerase
97
DNA polymerase
reads 3' - 5', writes 5' - 3' with complementary bases
98
DNA ligase
fill in gaps in Okazaki fragments
99
Okazaki fragments
found in lagging strand because it is made in pieces - DNA polymerase falls off when new strand encounters previously synthesized strand
(leading strand is made continuously)
100
process of DNA translation
helicase unwinds DNA, DNA polymerase reads and matches template strand, creates two identical DNA double helices
101
semiconservative translation
one original DNA strand, one daughter strand
102
Transcription
info in DNA converted to RNA
103
Transcription initiation
in promoter region
- up 5' end from start of transcription
- Transcription factors bind to TATA box, recruits RNA polymerase
- RNA polymerase binds and is activated, transcription begins
104
TATA box
thymine and adenine repeating sequence in DNA that signals where transcription can begin, transcription factors bind to
105
Transcription Elongation
RNA sequence produced and elongated because of RNA polymerase
106
RNA polymerase
causes DNA to unwind, starts reading 3' to 5', no primer needed, synthesizes RNA 5' to 3', catalyzes phosphodiester bonds
107
RNA polymerase 1
rRNA
108
RNA polymerase 2
mRNA or snRNA
109
RNA polymerase 3
rRNA or tRNA or snRNA
110
what are the RNA bases
adenine, cytosine, guanine, uracil
111
why is RNA less stable than DNA
ribose sugar with OH group on 2' carbon, less stable because of possible nucleophilic attack against sugar backbone
112
can RNA fold
yes bcs it is single stranded, form hydrogen bonds between bases
113
RNA as an enzyme
- found in spliceosomes which edit mRNA
- found in ribosomes which aid protein synthesis
114
messenger RNA (mRNA)
forms a template for protein synthesis
115
Transfer RNA (tRNA)
carries activated amino acids to ribosomes for protein synthesis
116
Ribosomal RNA (rRNA)
structural core of ribosomes
117
Small nuclear RNA (snRNA)
involved in processing of DNA and RNA in nuclei (functions in nucleus)
118
5' capping
post-transcriptional modification, modified guanine nucleotide attached to a 5' triphosphate bridge
- protects from 5' - 3' exonuclease degradation
119
exonuclease degradation
from the ends of the nucleus (not from the middle)
120
3' polyadenylation
post-transcriptional modification, addition of 50-250 adenosine monophosphates
- protects from 3' - 5' exonuclease degradation
121
mRNA splicing
post-transcriptional modification, intron cut out from RNA, exons spliced together
122
intron
non-coding region
123
spliceosome
made of snRNPs, cut mRNA and join (ligates) cut ends
124
Alternative splicing
only some exons present in RNA transcript to code for different proteins (multiple proteins possible from one gene)
125
what direction is RNA read in translation
mRNA read 5'-3', bases read in triplets
126
Codon
triplet of bases, each codon codes for specific amino acid, most have multiple codons
127
Wobble Hypothesis
how tRNA interacts with mRNA, amino acid carried by tRNA corresponds to codon which RNA binds
- only first two bases need to match precisely
128
what pairing is common in Wobble theory
G / U
129
Open Reading Frame
coding region of mRNA, need to find right start position or can cause a frameshift
130
Start codon
AUG (methionine)
131
Stop codon
UAA, UGA, UAG don't code for protein, release factors bind to ribosome to terminate translation
132
point mutation
single base added, deleted, or changed
133
frameshift mutation
reading from point on changes
134
missense mutation
changed base causes different amino acid
135
nonsense mutation
change in base causes premature stop codon
136
silent mutation
changed base has no effect
137
Ribosomes
read mRNA and translate to proteins
138
Ribosome small subunit
binds and reads mRNA (at 5' cap), recruits large ribosomal unit when it finds AUG (start)
139
Ribosome large subunit
rRNA complexed with proteins, docking site for tRNAs, catalyzes peptide bonds between amino acids released from tRNAs
140
A - docking site for large subunit
tRNA arrives with amino acid linked to it
141
P - docking site for large subunit
where polypeptide chain grows
142
E - docking site for large subunit
where tRNA that has given up amino acid is going to exit
143
Charging tRNA
empty tRNA needs new amino acid, "charged" by aminoacyl-tRNA synthetase
- binding site for AA, ATP, and empty tRNA
- ATP cleavage provides energy to link AA to tRNA via ester bond
144
Translation initiation
- small subunit binds to 5' cap of mRNA
- tRNA with anticodon UAC binds AUG start codon ATP
- large subunit is recruited
145
Translation Elongation
peptide bond between AA1 and AA2, APE until stop codon reached causing release factor, protein released and ribosome dissociates
146
Reversible RNA post-translational modifications
addition of a group or molecule
- phosphorylation, ubiquitylation, glycosylation
147
Irreversabe RNA post-translational modifications
remove a group or cleavage protein (proteolysis)
148
Smooth endoplasmic reticulum
lacks ribosomes, cellular detoxification, storage of calcium ions
149
rough endoplasmic reticulum
ribosomes on surface, biosynthesis, folding, maturation, stabilization, trafficking of transmembrane and secretory proteins
150
proteostasis
protein homeostasis: maintain amount of proteins synthesized, monitor protein quality
151
Cotranslational - Translocation
how protein gets into rough ER from cytosol
1. SR-SRP complex brings hydrophobic polypeptide to ER
2. whole complex brought to translocon (sec6), SR-SRP complex leaves.
3. Hydrophobic polypeptide is looped into the translocon, and binds a recognition site
4. the hydrophobic loop pushes open plug at bottom of translocon, signal peptide leaves through lateral gate
5. polypeptide is released into ER lumen at the end of translation for PTM
152
Insertion of multi-pass transmembrane proteins in rough ER
the signal recognition particle and its receptor are required to initiate the translocation of the first transmembrane domain, threading of subsequent transmembrane domains managed by ribosome-translocon assembly and hydrophobicity of the translated domain
153
N terminus
first amino acid w/ free amino group carboxylic group of AA1
154
C terminus
last amino acid w/ free carboxyl group linked to amino group of AA2 (forms peptide bond)
155
What happens in the rough ER
chaperones assist nascent proteins to fold and undergo modification including glycosylation, disulfide bond formation, and oligomerization
- properly folded proteins packed into vesicles and shipped to golgi apparatus
156
nascent proteins
unmature
157
what happens to improperly folded proteins
undergo degradation in the cytosol by proteasomes
158
Golgi Apparatus
sorting and dispatch station for ER products
159
how do vesicles enter the GA
vesicles enter via the cis face (towards nucleus), (trans face towards cell membrane), are transported through membrane-enclosed cisternae
160
where do modifications take place in GA
take place as they move through cisternae
161
Lysosome - protein modification and tagging
contain proteolytic and degradative enzymes
162
ER associated degradation pathway
degrades troubled proteins by ubiquitin-proteasome system
- cell recognizes protein as misfolded
- retrotranslocation: protein kicked out of lumen to cytosol
- protein is degraded by proteosome
163
Ubiquinatation of protein
protein tagged to identify as misfolded
164
Unfolded protein response
activated when ERAD can't handle misfolded proteins, cell adjust protein folding pathways in the cell
- autophagy is last resort if ER stress continues
165
vesicle
enclosed lipid bylayer w/ cytoplasm, carries materials, budding off an existing membrane, proteins coating vesicle determines destination
166
COP II
vesicle ER to Golgi apparatus
167
COP 1
vesicle from golgi to ER
168
clathrin
vesicle from plasma membrane (receptor-mediated endocytosis)
169
Exocytosis - SNARE complex
repulsive forces because of hydrophilic heads on phospholipids btwn membrane and vesicle, SNARE complex helps to overcome forces
170
V-SNARE
proteins on vesicle (VAMP and synaptobrevin)
171
T-SNARE
proteins on membrane (Syntaxin, SNAP-25)
172
synaptotagmin
calcium binding protein on vesicle, activates SNARE complex
173
Trafficking of vesicles and cytoplasmic proteins
roads are the cytoskeleton
vehicles are the motor proteins
174
intermediate filaments
part of cytoskeleton, structural function only, made up of individual keratin filaments, rope like consistency, strong and flexible
175
microtubules
part of cytoskeleton, structural and long distance transport
176
f-actin
part of cytoskeleton, short distance transport
177
actin filament
two strands of globular actin monomers, less strong and stable
178
actin filament and microtubules polarity
plus end - toward membrane
minus end - toward nucleus
(non electrical polarity)
179
kinesin motor protein
transport vesicles on the microtubles towards plus end
180
dynein motor protein
transport vesicles on the microtubles towards minus end
181
myosin V
transport vesicle moves towards plus end on F-actin
182
myosin VI
transport vesicle moves towards minus end on F-actin
183
Cell junctions
how cells connect to eachother and cellular matrix
184
Gap junction
mediates cell-to-cell communication
- form intercellular channels that allow movement of ions and small molecules between cells
185
how are gap junction channels formed
composed of hexamers of integral proteins,
connexin > 6 form connexin > 2 form intercellular channel that connects cytoplasms
186
how do gap junctions couple cells
electrically and metabolically, found in most cells (bone, nerves, muscles) attached to something solid
187
isoforms of connexins
permit tissue-specific gap junctions
- different combinations of connexions create channels that differ in permeability and regulation
- closed ve open caused by ph, calcium, or neurotransmitter changes
- rapid turnover of connexons
188
Tight junctions
hold cells closely together near apex, to prevent molecules from leaking across the epithelium
189
apical region
area facing the external environment
190
Claudin
main transmembrane protein in tight junctions, linked to the cytoskeleton
- seal is selectively permeable
191
impaired tight junction barrier function
dysregulation of claudins dysregulated in various cancers, luminal bacterial leakage inversely exacerbates inflammation
192
tumorigenesis
contributed to by epidermal growth factors influx
193
loose connective tissue proper
areolar, adipose, reticular
194
dense connective tissue proper
regular, irregular, elastic
195
supportive connective tissue
cartilage, bones
196
fluid connective tissue
blood and lymph
197
Areolar connective tissue
underlies most epithelia, fills paces between muscle fiber, surrounds blood and lymph vessels, least specialized may contain all cells and fibers
198
collagen fibers
straight and unbranched fibrous protein subunits linked together, flexible with great tensile strength to resist stretching
199
elastic fibers
contain the protein elastin, along with lesser amounts of other proteins and glycoproteins
- returns to original shape after being stretched or compressed
200
reticular fibers
same proteins as collagen, narrow network of branched fibers
201
mesenchymal cell
multipotent adult stem cell, can differentiate into any type of connective tissue cells needed for repair (fibroblast, macrophages, adipocytes, etc)
202
fibroblast
in all connective tissue proper, produces matrix
- secrete polysaccharides and proteins, collagen, glycosaminoglycans, proteoglycans
- secretions produce a viscous ground substance
203
fibrocytes
small, spindle like, precursor to fibroblast
204
macrophages
large phagocytic cells that release cytokines to recruit other immune system cells
205
mast cells
contain granules that cause vasodilation and prevents coagulation
206
microphages
(neutrophils and eosinophils) that attack pathogens
207
ground substance
clear, viscous, colorless matrix that absorbs shock
208
proteoglycans
attracting and trapping water, polypeptide sequence with glycosaminoglycans
209
glycosaminoglycans
repeating disaccharide units have negatively charged groups that interact with water, absorb load by releasing water by deforming under stress
210
Adipose tissue
mostly fat storage cells with little extracellular matrix
211
ectopic fat accumulation
areas other than subcutaneously below the skin
212
reticular tissue
mesh-like supportive framework for soft organs
- fibroblastic reticular cells produce the reticular fibers that form the network onto which other cells attach
213
Dense regular connective tissue
parallel to eachother, enhancing tensile strength, resistance to stretching in one direction (ligaments and tendons)
214
Dense irregular connective tissue
direction of fibers is random, greater strength in all directions
215
Elastic dense connective tissue
enables structure to regain original shape after stretching (arteries, vocal cords, trachea, bronchial tubes)
216
Hyaline cartilage supportive connective tissue
- mature chondrocytes seen in the lacunae
- hazy and glass like matrix indicates dispersed collagen fibers and large amounts of proteoglycans
- found at ends of bones, strong and flexible
217
Fibroelastic cartilage supportive connective tissue
- chondrocytes in lacunae arrange in clusters or alternate rows
- tough, thick bundles of collage fibers dispersed through its matrix
- limits movement, prevents bone-bone contact, resists compression
218
Elastic cartilage supportive connective tissue
supportive but bends easily
219
bone
compact and spongy, mostly collagen fibers embedded in mineralized ground substance containing hydroxyapatite
220
Anchoring junctions
adhere cells to other cells or the extracellular matrix
- strong membrane-spanning structure that is tethered inside the cell to the tension-bearing filaments of the cytoskeleton
221
types of anchoring junctions
adherens junctions, desmosomes, hemidesmosomes, focal adhesions
222
Adherens junction
located on apical side but below tight junctions
- formation of AJs prerequisite for TJ
- over 170 proteins colocalize with cadherin or catenins in AJs
- cadherin structure dependence on CA2+ ions
- connected to cytoskeleton by actin filament
223
Desmosome
- different type of cadherin than in AJ
- connected to cytoskeleton by intermediate filament
- role in tissue subjected to mechanical stress (myocardium, bladder, skin)
224
E-cadherins (epithelial)
mutation in cadherin often found in cancer cells, metastatic potential of cells
225
Hemidesmosomes and focal adhesion
- links cell to extracellular matric
- integrins common to both
226
how are focal adhesions linked to the cytoskeleton
with actin filaments
227
how are hemidesmosomes linked to the cytoskeleton
with intermediate filaments
228
Functions of cell junctions
- attachment and mechanical support (AJs)
- Sepatation, protection and traffic regulation
- communication between cells: Mechanical (AJ), electrical and metabolic (GJ)
229
cell polarity
orientation of the cell to establish apical and basal surfaces
230
Epithelial tissue
sheets cover all surfaces of body exposed to outside world and lining outside organs
- forms much of the glandular tissue
- supported by connective tissue
231
endothelium
lines the surface of the circulatory system
232
simple squamous
regulates the passage of substances into underlying tissue
233
simple cuboidal
absorb and secrete substances
234
simple columnar
absorption, secretion, usually has apical cilia or microvilli
235
stratified squamous
protection against microorganisims and water loss
236
stratified cuboidal
protective, secretion
237
stratified columnar
protection and secretion
238
pseudostratified columnar
absorption and secretion of mucus, protection from foreign particles
239
transitional epithelium
several layers of cells, become flattened when stretched
240
characteristics of epithelial tissue
- specialized contacts
- polarity (apical and basal surface)
- avascular (get nutrients through diffusion)
- innervated
- regenerative
241
functions of epithelial
- protection (stratified)
- secretion (cuboidal)
- absorption (cuboidal, columnar)
- excretion
- filtration
- diffusion
- sensory reception
242
Fluid connective tissue
blood and lymph
- cells circulate in liquid extracellular matrix
- blood pressure causes plasma to leak into interstitial space and reabsorbed back into the blood vessels
243
lymph
interstitial fluid that has entered lymphatic system
244
functions of connective tissue proper
connect and protect, store energy reserves
245
functions of supporting connective tissue (cartilage and bone)
structural strength
246
function of fluid connective tissue
transport dissolve materials, protection from pathogens
247
Integumentary system
epidermis, dermis, hypodermis
largest organ, 16% of body weight
248
Epidermis
made of keratinized, stratified squamous epithelium (4 to 5 layers depending on location)
249
layers of the epidermis
Corneum, Lucidum, Granulosum, Spinosum, basale (come lets go sun bathing)
250
Stratum Granulosum
3-5 rows of flattened cells
- undergo keratinization because too far from nutrients
250
Stratum basale (germinativum)
single layer of cuboidal mitotic stem cells give rise to keratinocytes
- 10-25% are melanocytes
- some are tactile and epidermal dendritic cells
- forms epidermal ridges
250
Stratum spinosum
8-10 cell layers of keratincocytes
- keratinocytes held together by desmosomes
- irregular in shape - artifact of processing
251
Keratonylanine granules
aid in cell dehydration, cross linking keratin filaments, keratinization
252
Stratum locidium
2-3 rows of flat, dead keratinocytes
- clear appearance due to eleidin
- present only in thick skin
253
Stratum corneum
20-30 layers of horny scales made of dead keratinocytes
- 3/4 of thickness
- glycoproteins for water-resistance
- dead keratinocytes secrete defensin
254
merkel cells
touch receptors, membranes interact with free nerve endings
255
melanocytes
pigment
- between cells in stratum basale
- responsible for pigment from UV response
- accumulates in vesicles called melanosomes
256
Albinism
pale, milky skin, flaxen hir, light irises due to defect in enzyme used to make melanin
257
Vitiligo
melanocytes die in patches, autoimmune origing
258
Cyanosis
bluish discoloration of skin or mucous membrane, caused by disorders of abnormal hemoglobin
259
jaundice
yellowing of skin, whites of eyes because of high level of bilirubin (usually inserted into bile in liver)
260
carotenemia
pigmentation due to high carotene levels in the blood (excessive consumption of fruits and veggies)
261
Papillary layer of dermis
20% of thickness
- composed of areolar connective tissue
- most immune cells
262
dermal papillae
superior surface projections, contain capillary loops, Meissner corpuscles, free nerve endings (pain)
263
Reticular layer of dermis
80% of thickness, composed of dense irregular connective tissue
264
Cleavage (tension) lines
formed by collagen and plastic fibers in the dermis
- arranged in parallel bundles
- resist force in a specific direction
- parallel cut remains shut, cut across causes scar
265
components of the dermis
blood vessels, hair follicles, sebaceous glands, sweat glands, arrector pili muscle
266
Markel cells
sustained pressure, slowly adapt to stimuli
267
Meissner's corpuscle
detect light pressure - adapt quickly to stimuli
268
free nerve endings
pain
269
Ruffini corpuscle
detect stretch, deformation in joints, warmth
270
lamellated corpuscle (pacinian)
deep pressure - adapt quickly
271
which sensory receptors are mechanoreceptors
markel, meissner's, pacinian, ruffini
272
hypodermis
not really part of skin = superficial facia
- composed of adipose and areolar connective tissue: anchors skin to underlying structures
273
Function of integument
Protection (chemical, physical, biological), Thermoregulation, Sensory reception, Blood reservoir, Excretion, Metabolic functions
274
