Biology Midterm 2 Flashcards
1
Q
Interphase
A
The period from cell formation to cell division - Carrying out all routine activities
2
Q
G1
A
Cell cycle subphase: Metabolically active, synthesizing proteins and rapid growth
3
Q
S phase
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Cell cycle subphase: DNA is replicated
4
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G2
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Cell cycle subphase: brief final phase of interphase; prepares for cell division (centriole replication complete
5
Q
Replication bubble
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Bubble formed after enzymes unwind DNA
6
Q
Replication fork
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The point at which DNA strands unzip
7
Q
DNA polymerase
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The enzyme that travels along the DNA template strands, forming two new complementary strands
8
Q
Semi conservative replication
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Each new DNA molecule consists of one old and one new nucleotide strand
9
Q
M (mitotic phase)
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Cell division: Involves mitosis and cytokinesis
10
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Mitosis
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The division of the nucleus (cell division)
11
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Cytokinesis
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The division of the cytoplasm
12
Q
Cleavage furrow
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A furrow that forms during cytokinesis to pinch off the two new daughter cells
13
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mRNA (messenger RNA)
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Nucleotide strands resembling “half-DNA’ molecules (one of two DNA strand complementary molecules for protein structure)
14
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rRNA
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Forms ribosomes (consists of two subunits - one large, one small)
15
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Transcription
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Transfers information from a DNA base sequence to complementary mRNA
16
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Promoter
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Special DNA sequence that contains the start point of a gene to be transcribed
17
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RNA polymerase
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The enzyme that oversees the synthesis of mRNA
18
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Translation
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Translates mRNA to proteins (from base sequence to amino acid sequence)
19
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Genetic code
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Rules by which the base sequence of a gene is translated into an amino acid sequence
20
Q
Codon
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The corresponding three-base sequence on mRNA for each DNA triplet
21
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Anticodon
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A three-base sequence, which binds to the mRNA codon calling for the amino acid carried by that particular tRNA
22
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Initiation
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Ribosomal subunit binds to initiator tRNA and scans mRNA for the start codon (AUG)
23
Q
Elongation
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Ribosomes moves along mRNA in one direction, generating amino acids forming the polypeptide chain
24
Q
Elongation steps
A
a. Codon recognition
Aminoacyl-tRNA binds to complementary codon in A site of ribosome
b. Peptide bond formation
Enzymatic component in large ribosomal subunit catalyzes peptid bond formation between the amino acid of the tRNA in the P site and that of the tRNA in the A site
c. Translocation
The ribosome moves, shifting its position one codon along the mRNA. This shift moves tRNA in the A site to the P site. Vacant tRNA is transferred to the E site to be released and recharged with another amino acid.
25
Termination
mRNA strand is read sequentially until the stop codon (UGA, UAA, or UAG) enters the A site. Signals that translation of mRNA is finished and water is added to the polypeptide chain to break the bond between the chain and the tRNA in the P site. The completed polypeptide chain is then released from the ribosome
26
ER signal sequence
Short "leader" peptide - When present in a protein being synthesized the associated ribosome attaches to the membrane of the rough ER
27
MicroRNAs (miRNAs)
Small RNAs that can interfere with and suppress mRNAs made by certain exons, effectively silencing them
28
Small interfering RNAs (siRNAs)
Like miRNA but originate from outside the cell
29
Autophagy
(self-eating) Sweeps up bits of cytoplasm and unneeded organelles into double-membrane vesicles called autophagosomes. They are then delivered to lysosomes for digestion of contents which cell reuses
1. Allows cells to dispense of unneeded proteins and worn out organelles
2. In times of stress can cannibalize to survive
3. Helps to restructure the cells
30
Ubiquitin-proteasome pathway
Handles individual proteins that are misfolded, damaged, or unneeded and must be disposed of
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Ubiquitins
Markers for proteins needing destruction
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Proteasomes
Waste disposal complexes composed of protein-digesting enzymes
33
Apoptosis
Programmed cell death; rids the body of cells that are programmed to have a limited life span (cells in uterus and webs between fingers and toes of developing fetus)
34
Hyperplasia
Accelerated growth; in anemic people this results in accelerated growth of red blood cells
35
Atrophy
A decrease in size of an organ or body tissue
36
Tissues
Groups of cells that are similar in structure and perform a common/related function
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Histology
The study of tissues
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Fixed
Preserved (as relating to microscopy)
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Sections
Slices (as relating to microscopy)
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Artifacts
Minor distortions in preserved tissue after it has been exposed to many procedures that alter its original condition (as relating to microscopy)
41
Epithelial tissue
Epithelium; A sheet of cells that covers a body surface or lines a body cavity
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Covering and lining epithelium
Forms the outer layer of the skin; dips into and lines the open cavities of the urogenital, digestive, and respiratory systems; and covers the walls and organs of the closed ventral body cavity
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Glandular epithelium
Fashions the glands of the body
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Epithelium functions
```
1 Protection
2 Absorption
3 Filtration
4 Excretion
5 Secretion
6 Sensory reception
```
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Apical surface
Not attached to surrounding tissue and is exposed to either the outside of the body or the cavity of an internal organ
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Basal surface
Attached to underlying connective tissue
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Apical-basal polarity
The polarity between the apical and basal surfaces
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Microvilli
Finger like extensions of the plasma membrane to increase surface area
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Basal lamina
Thin supporting sheet adjacent to basal surface of epithelium - Consists largely of glycoproteins secreted by epithelial cells + collagen fibers. Acts as selective filter determining which molecules diffusing from the underlying connective tissue are allowed to enter the epithelium. Also can act as scaffolding along which epithelial cells can migrate to repair a wound
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Basement membrane
In between the epithelial and connective tissues that reinforces the epithelial sheet, helps it resist stretching and tearing, and defines the epithelial boundary
Consists of basal lamina and reticular lamina
51
Reticular lamina
Deep to the basal lamina: consists of a layer of extracellular material containing a fine network of collagen protein fibers that "belongs to" the underlying connective tissue
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Simple epithelia
Consist of a single cell layer - typically found where absorption, secretion, and fitration occur and a thin epithelial barrier is desirable
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Stratified epithelia
Composed of two or more cell layers stacked on top of each other; common in high-abrasion areas where protection is important, such as the skin surface and lining of the mouth
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Squamous cells
Flattened and scale-like cells
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Cuboidal cells
Boxlike cells, approximately as tall as they are wide
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Columnar cells
Tall and column shaped cells
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Simple squamous epithelium
Cells flattened laterally with a sparse cytoplasm - Allows materials to pass by diffusion and filtration in sites where protection is not important: kidney glomuleri, air sacs of lungs, lining of heart, blood vessels etc
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Endothelium
Provides a slick, friction-reducing lining in lymphatic vessels and in all hollow organs of the cardiovascular system; Cpillaries - efficient exchange of nutrients and wastes between the bloodstream and surrounding tissue cells
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Mesothelium
The epithelium found in serous membranes, the membranes lining the ventral body cavity and covering its organs
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Simple cuboidal epithelium
Consists of a single layer of cells as tall as they are wide - secretion and absorption. Forms the walls of the smallest ducts of glands and many kidney tubules
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Simple columnar epithelium
Single layer of tall, closely packed cells, aligned like soldiers in a row; lines the digestive tract from the stomach through the rectum. Mostly associated with absorption and secretion and the digestive have 2 modifications: Dense microvilli on apical surface of absorptive cells 2 Tubular glands made of cells that secrete mucus-containing intestinal juice
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Psuedostratified columnar epithelium
Vary in height; all cells rest on basement membrane but only the tallest reach the free surface of the epithelium. Because cell nuclei lie at different levels above the basement membrane, the tissue gives false (pseudo) impression that several layers are present. Short cells relatively unspecialized and give rise to the taller cells. Secretes or absorbs substances; ciliated version containing mucus-secreting goblet cells lines most of the respiratory tract
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Stratified squamous epithelium
Most widespread of the stratified epithelia. Composed of several layers, it's thick and well suited for protection. Free surface cells are squamous and cells of deeper layers are cuboidal or columnar. This epithelium forms the external surface of the skin and exends a short distance into every body opening that is directly continuous with skin (outer layer of epidermis is keratinized for tough protection)
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Stratified cuboidal epithelium
Quite rare mostly found in the ducts of some of the larger glands
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Stratified columnar epithelium
Limited distribution in the body. Small amounts found in the pharynx, male urethra, and lining some glandular ducts. This epithelium also occurs at transition areas or junctions between two other types of epithelia. Only its apical layer of cells is columnar
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Transitional epithelium
Forms the lining of hollow urinary organs, which strech as they fill with uring. Cells of its basal layer are cuboidal or columnar. Apical cells vary in appearance, depending on the degree of distension (stretching of the organ)
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Gland
Consists of one or more cells that make and secrete a particular product
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Secretion
An aqueous fluid that usually contains proteins
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Endocrine glands
Lose their ducts during development (ductless glands) Produce hormones
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Hormones
Chemical messengers that they secrete by exocytosis directly into the extracellular space. Travel to specific target organs
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Exocrine glands
Secrete their products onto body surfaces or into body cavities. Unicellular glands do so by exocytosis whereas mutlicellular glands do so via an epithelium-walled duct that transports the secretion to the epitheliual surgace
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Unicellular glands
Mucous cells and goblet cells. Sprinkled in the epithelial linings of the intestinal and respiratory tracts amid columnar cells with other functions
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Mucin
A complex glycoprotein that dissolves in water when secreted. Once dissolved, mucin forms mucus, a slimy coating that protects and lubricates surfaces
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Goblet cells
Accumulating mucin distends the top of the cell, making the cells look like a glass with a stem
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Multicellular exocraine glands
Structurally complex with two basic parts: epithelium derived duct and secretory unit (acinus), consisting of secretory cells. In all but the simplest glands, supportive connective tissue surrounds the secretory unit, supplies it with blood vessels and nerve fibers, and forms a fibrous capsule that extends into the glands and divides it into lobes
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Simple glands
Have an unbranched duct (classification of glands)
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Compound glands
Have a branched duct (classification of glands)
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Tubular
Secretory cells form tubes (categorization of glands by secretory units)
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Alveolar
Secretory cells form small, flasklike sacs (categorization of glands by secretory units)
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Tubuloalveolar
Both types of secretory units (categorization of glands by secretory units)
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Acinar
Interchangeable with alveolar
82
Merocrine glands
Secrete their products by exocytosis. Not altered in any way ("merely secrete") Pancreas, sweat glands, and salivary glands
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Holocrine glands
Secretory cells accumulate their products within them until they rupture. Cells "die for the cause"
84
Connective tissue
```
Binds and supports, protects, insulates, and stores reserve fuel
4 classes:
Connective tissue proper
Cartilage
Bone
Blood
```
85
Extracellular matrix
Separates the living cells of the tissue
86
Common origin
All connective tissues arise from mesenchyme (an embryonic tissue)
87
Ground substance
Unstructured material that fills the space between the cells and contains the fibers
Interstitial fluid
Cell adhesion proteins
Proteoglycans
88
Interstitial fluid
The ground substance consists of large amounts of fluid and functions as molecular sieve through which nutrients and other dissolved substances can diffuse between blood capillaries and cells
89
Cell adhesion proteins
Serve mainly as connective tissue flues that allows connective tissue cells to attach to the extracellular matrix
90
Proteoglycans
Consist of a protein core to which large polysaccharides called glycosaminoglycans (GAGs) are attached. The strand-like GAGs stick out from the protein core like the fibers of a bottle brush.
91
Collagen fibers
Constructed primarily of the fibrous protein collagen. Secreted into the extracellular space where they assemble spontaneously into cross-linked fibrils, which in turn are bundled together into the thick collagen fibers seen in the microscope. Extremely tough and provide high tensile strength to the matrix
92
Elastic fibers
Long, thin, elastic fibers form branching networks in the extracellular matrix. These fibers contain a rubber-like protein, elastin, that allows them to stretch and recoil like rubber bands.
93
Reticular fibers
Short, fine fibers made of a different type of collagen than the more common, thicker collagen fibers. Connect to the coarser collagen fibers but they branch extensively, forming delicate network that surround small blood vessels and support the soft tissue of organs. Allow more stretch than the larger collagen fibers
94
Fibroblasts
In connective tissue proper become firbocytes
95
Chondroblasts
In cartilage become chondrocytes
96
Osteoblasts
In bone become osteocytes
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Adipocytes
Adipose or fat cells which store energy as fat
98
White blood cells
WBCs or leukocytes (neutrophils, eosinophils, and lymphocytes) and other cell types that are concerned with tissue response to injury
99
Mast cells
Cluster along blood vessels. Oval cells detect foreign microorganisms and initiate local inflammatory responses against them. (Heparin - prevents blood clotting / Histamine - A substance that makes capillaries leaky / Proteases (protein degrading enzymes / other enzymes)
100
Macrophages
Large, irregularly shaped cells that avidly devour a broad variety of foreign materials, ranging from foreign molecules to entire bacteria to dust particles.
101
Mesenchyme
A fluid ground substance containing fine sparse fibers and star-shaped mesenchymal cells. Arises during the the early weeks of embryonic development and eventually differentiates into all other connective tissue cells (some mesenchymal cells remain and provide a source of new cells in mature connective tissues)
102
Connective tissue proper
Composed of loose connective tissues (areolar, adipose, and reticular) and dense connective tissues (dense regular, dense irregular, and elastic)
103
Areolar connective tissue
Most widely distributed connective tissue in the body; serves as universal packing material between other tissues. Binds body parts together while allowing them to move freely over one another. Made up of elastic fibers, ground substance, fibroblast nuclei, and collagen fibers
104
Adipose (fat) tissue
Similar to areolar tissue in structure but its nutrient-storing ability is much greater. Matrix is scanty and cells are packed closely together. Also helps prevent heat loss (insulation)
105
Reticular connective tissue
Resembles areolar connective tissue but only fibers in the matrix are reticular fibers forming a delicate network along which fibroblasts called reticular cells are scattered. Forms a labyrinth-like stroma or internal framework that can support many free blood cells in lymph nodes, the spleen, and bone marrow.
106
Stroma
"bed" or "mattress"
107
Dense regular connecttive tissue
Contains closely packed bundles of collagen fibers running in the same direction, parallel to the direction of pull. This arrangement results in white, flexible structures with great resistance to rension where the tension is exerted in a single direction. (Tendons (muscle to bone), aponeuroses (muscles to other muscles or bones) ligaments (bind bones together at joints))
108
Dense irregular connective tissue
Has same structural elements as regular variety but bundles of collagen fibers are much thicker and are arranged irregularly; they run in all directions. This tissue forms sheets where tensions is exerted in many different directions (Skin as dermis, and forms fibrous joint capsules and fibrous coverings that surround some organs)
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Elastic connective tissue
A few ligaments, such as those connecting adjacent vertebrae, are very elastic. Dense regular tissue in these structures is elastic connective tissue (many larger arteries have stretchy sheets of elastic connective tissue in their walls)
110
Cartilage
Stands up to both tension and compression. Qualities between dense connective tissue and bone. Tough but flexible, providing resilient rigidity to the structures it supports.
111
Hyaline cartilage
Provides firm support with some pliability:
Ends of long bones (springy compression pads)
Supports tip of nose
Connects ribs to sternum
Supports most of respiratory system passages (trachea)
Makes up most of the embryonic skeleton before bone forms
112
Elastic cartilage
Nearly identical to hyaline cartilage but elastic cartilage has many more elastic fibers.Found where strength and exceptional stretchability is needed (skeletons of external ear and epiglottis (flap covering opening to respiratory passageway in the throat))
113
Fibrocartilage
Intermediate between hyaline cartilage and dense regular connective tissue. Rows of chondrocytes (a cartilage feature) alternate with rows of thick collagen fibers (dense regular connective tissue). Because it resists both compression and tension well, fibrocartilage supports as well as withstands heavy pressure (resilient cushions between bony vertebrae and spongy cartilages of the knee)
114
Bone
Exceptional ability to support and protect body structures. Provide cavities for storing fat and synthesizing blood cells. Hard and rigid matrix - inorganic calcium salts (bone salts)
115
Blood
Fluid withing blood vessels and the most atypical connective tissue. Does not connect things or give mechanical support. Classified as connective tissue because it develops from mesenchyme and consists of blood cells surrounded by a nonliving fluid matrix called blood plasma.Fibers of blood are soluble protein molecules that precipitate, formind visible fiberlike structures during blood clotting. Transport vehicle for cardiovascular system
116
Muscle tissues
Well-vascularized tissues responsible for body movement
117
Myofilaments
Elaborate networks of actin and myosin filaments that bring about movement or contraction in all cell types
118
Skeletal muscle
Packaged by connective tissue sheets into organs called skeletal muscles that are attached to the bones of the skeleton. Form the flesh of the body and as they contract they pull on bones or skin, causing body movements
119
Muscle fibers
(Skeletal muscle cells) Long, cylindrical cells that contain many peripherally located nuclei
120
Cardiac muscle
Found only in the walls of the heart. Contractions help propel blood through the blood vessels to all parts of the body. Cardiac muscle cells are striated and are generally uninucleate with nucleus situated centrally and branching cells that fit together tightly at unique junctions (intercalated discs)
121
Smooth muscle
Cells have no visible striations. Spindle shaped cells and contain one centrally located nucleus. Found mainly in walls of hollow organs other than the heart. Squeezes substances through these organs by alternately contracting and relaxing
122
Neurons
Highly specialized nerve cells that generate and conduct nerve impulses
123
Cutaneous membrane
Skin; consists of keratinized stratified squamous epithelium (epidermis) firmly attached to thick layer of connective tissue (dermis
124
Mucous membranes
(Mucosae) Line all body cavities that open to the outside of the body. Moist membranes bathed by secretions (urine in urinary tract)
125
Lamina propria
Layer of areolar connective tissue. Sometimes rests on a third (deeper) layer of smooth muscle cells
126
Pleurae
Serous membrane lining the thoracic wall and covering the lungs
127
Pericardium
Serous membrane enclosing the heart
128
Peritoneum
Serous membrane that encloses the abdominopelvic viscera
129
Regeneration
Replaces destroyed tissue with the same kind of tissue
130
Fibrosis
Replaces destroyed tissue with scar tissue (dense connective tissue)
131
Granulation tissue
Delicate pink tissue that contains capillaries that grow in from nearby areas and lay down a capillary bed
132
Primary germ layers
Lie one atop the next in the first events of embryonic development consisting of the ectoderm (nervous tissue), mesoderm (muscle and connective tissue), and endoderm (inner lining of digestive system)
133
Subcutaneous tissue
Superficial to the tough connective tissue wrapping skeletal muscles .Not part of the skin but shares some protective functions. Consists of adipose tissue with some areolar connective tissue. Anchors the skin to underlying structures (muscles)
134
Epidermis
Outermost layer of skin - consists of four distinct cell types and 4-5 distinct layers
135
Keratinocytes
Cells that produce keratin - firbous protein that helps give epidermis its protective properties
136
Melanocytes
Spider-shaped epithelial cells that synthesize melanin (pigment) found in the deepest layer of the epidermis
137
Dendritic cells
Star shaped cells arising from bone marrow and migrate to the epidermis. Ingest foreign substances and key activators for immune system
138
Tactile epithelial cells
Present at the epidermal-dermal junction. Shapes like a spiky hemisphere, each tactile epithelial cell is intimately associated with a disclike sensory nerve ending
139
Thick skin
Covers areas subject to abrasion; consists of five layers (stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum)
140
Stratum basale
Deepest epidermal layer. Single row of stem cells continually renewing cell population
141
Stratum spinosum
(prickly layer) Several cell layers thick. Many spinelike extensions of its keratinocytes. Contain thick bundles of intermediate filaments, which consist of a tension-resisting protein, pre-keratin. Resist tension in the cell and are anchored to the desmosomes
142
Stratum granulosum
(granular layer) Consists of one to five cell layers in whic keratinocyte appearance changes drastically, and the process of keratinization begins.
143
Stratum lucidum
(clear layer) Found only in thick skin consists of a few rows of flat, dead keratinocytes. Cells idential to stratum corneum
144
Stratum corneum
(horny layer) Outermost epidermal layer braod zome of 20 to 3- cell layers thick. Keratin protects the skin against abrasion and penetration. Glycolipid between cells helps to waterproof. Cells shed regularly
145
Dermis
Made up of strong, flexible connective tissue. Cells typical of those found in connective tissue proper: fibroblasts, macrophages, and occasional mast cells and white blood cells. Semifluid matrix embedded with fibers binds the entire body together.
146
Papillary dermis
Areolar connective tissue in whic fine interlacing collagen and elastic fibers form a loosely woven mat with many small blood vessels
147
Dermal papillae
Peglike projections from papillary surface
148
Friction ridges
Skin ridges that help to grip certain kinds of surfaces
149
Reticular dermis
Coarse, dense irregular connective tissue. Network of blood vessles nourishing this layer lies between this and the subcutaneous tissue. Extracellular matrix contains thick bundles of interlacing collagen fibers.
150
Cleavage (tension) lines
Formed from separations, or less dense regions between the collagen fibers in the reticular dermis.
151
Flexure lines
Dermal folds that occur at or near joints where the dermis is tightly secured to deeper structures
152
Melanin
A polymer made of an amino acid called tyrosine. Range in colour from reddish yellow to brownish black. (pigment)
153
Carotene
A yellow to orange pigment found in certain plant products such as carrots. Accumulates in the stratum corneum and in the fat of the subcutaneous tissues. Can be converted to Vitamin A (essential for vision and epidermal health)
154
Hemoglobin
Oxygenated pigment of the blood
155
Skin appendages
Associated structures to skin (hair, hair follicles, nails, sweat glands, and sebacous (oil) glands)
156
Hairs (pili)
Flexible strands produced by hair follicles and consist largely of dead, keratinized cells.
157
Cuticle
(of hair) Formed from a single layer of cells overlapping one another like shingles on a roof to separate neighboring hairs so the hair does not mat. (most heavily keratinized part of the hair)
158
Hair follicles
The sheath of cells and connective tissue that surrounds the root of a hair
159
Hair bulb
Deep end of the follicle
160
Hair follicle receptor
A knot of sensory nerve endings (root hair plexus)
161
Peripheral connective tissue sheath
This connective tissue sheath is derived from the dermis. Forms the external layer of the follicle wall
162
Glassy membrane
At the junction of the fibrous sheath and epithelial root sheath. The basement membrane of the follicle epithelilum
163
Epithelial root sheath
Derived from the epidermis. Two components: external root sheath (direct continuation of epidermis) and internal root sheath (derived from matrix cells)
164
Hair matrix
Produces the actual hair shaft as well as the inner and outer root sheaths of hair
165
Arrector pili
Bundle of smooth muscle cells that can contract to pull the hair follicle upright (goosebumps)
166
Vellus hair
Body hair of children and adult females (pale and fine)
167
Terminal hair
Coarser, longer hair of the eyebrows, eyelashes, and scalp
168
Male pattern baldness
A genetically determined, gender-influenced condition that change the response of the hair follicles to androgens (shorter and shorter growth cycles)
169
Nail
Forms a clear protective covering on the dorsal surface of the distal part of a finger or toe
170
Nail matrix
The thickened proximal portion of the nail bed
171
Nail folds
Overlapped skin folds on the proximal and lateral boroders of the nail
172
Cuticle
Proximal nail fold projecting onto the nail body (eponychium)
173
Hyponychium
Thickened region beneath the free edge of the nail where dirt and debris tend to accumulate. Secures the free edge of the nail plate at the tip of the finger/toe
174
Sweat glands
(sudoriferous glands) Distributed over the entire skin surface except nipples and parts of external genitalia. Eccrine and apocrine glands: myoepithelial cells specialized to contract and force sweat into and through the gland's duct system to the skin surface (autonomic)
175
Eccrine sweat glands
More numerous than apocrine and are abundant on palms, soles of feet, and forehead. Simple, coiled, tubular gland. Temperate control, some antibacterial properties. Hypotonic filtrate of blood plasma secreted through exocytosis
176
Apocrine sweat glands
May act as sexual scent glands. Secretes filtrate of blood plasma with added proteins and fatty substances through exocytosis. Usually secreted at upper part of hair follicle; rarely the skin surface. Mostly located at axillary and anogenital regions
177
Ceruminous glands
Modified apocrine glands found in the lining of the external ear canal. Secretion mixes with sebum produced by nearby sebacous glands to form a sticky, bitter substance called cerumen, or earwax, that is thought to deter insects and block entry of foreign material
178
Mammary glands
Another type of specialized sweat gland that secretes milk.
179
Sebacous glands
(Oil glands) Simple branched alveolar glands found all over the body except for thick skin in palms and soles. Secrete sebum to lubricate skin and hair, help prevent water loss, and has antibacterial properties. Holocrine gland usually secreted from the upper part of the hair follicle.
180
Sebum
Oily substance that softens and lubricates the hair and skin, preventing the hair from becoming brittle and slows water loss from the skin. Also antibacterial
181
Acid mantle
Antibacterial (slightly acidic) film on the skin low in pH
182
Cutaneous sensory receptors
Exteroreceptors - Respond to stimuli arising outside the body
183
Basal cell carcinoma
Least malignant skin cancer (sun exposure)
184
Squamous cell carcinoma
Second most common skin cancer arises from the keratinocytes of the stratum spinosum
185
Melanoma
Cancer of the melanocytes (most dangerous because it is highly metastatic & resistant to chemotherapy)
186
Nervous system
Master controlling and communicating system of the body
187
Sensory input
Sensory receptors monitor changes occurring inside and outside the body gathering information as sensory input
188
Integration
Nervous system proceses and interprets sensory input and decides what should be done at each moment
189
Motor output
Nervous system activates effector organs (muscles and glands) to cause a response (motor output)
190
Central nervous system
(CNS) Consists of the brain and spinal cord; integrating control center of the nervous system
191
Peripheral nervous system
(PNS) Consists of nervs extending from the CNS and ganglia (collection of neuron cell bodies.
192
Sensory division of PNS
Consists of nerve fibers that convey impulses to the central nervous system from sensory receptors located throughout the body
193
Motor division of the PNS
Transmits impulses from the CNS to effector organs
194
Somatic nervous system
Composed of somatic motor nerve fibers that conduct impulses from the CNS to skeletal muscles (voluntary)
195
Autonomic nervous system
Consists of visceral motor nerve fibers that regulate the activity of smooth muscles, cardiac muscle, and glands. (involuntary)
196
Sympathetic division of ANS
Prepares body for stress: fight or flight mode
197
Parasympathetic division of ANS
Brings body out of "fight or flight" mode and returns to normal
198
Neuroglia
(Glial cells) Support and maintain neurons
199
Astrocytes
Most abundant and versatile glial cells. Support and brace neurons and anchor them to their nutrient supply lines (also help determine capillary permeability) Also control chemical environment around neurons (mop up leaked potassium ions)
200
Microglial cells
Touch nearby neurons, monitor their health, and when certain neurons are injured or in trouble microglial cells migrate toward them. Microglial cells turn into a special type of macrophage that phagocytozises the microorganisms or neuronal debris. (good because immune system has limited access to CNS)
201
Ependymal cells
Many are ciliated. Line the central cavities of the brain and spinal cord, where they form a fairly permeable barrier between the cerebrospinal fluid that fills those cavities and the tissue fluid bathing the cells of the CNS
