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GCU BIO 201 Exam 2 Test Questions and Answers Graded A+
Neuron Structure dendrites, cell body, axon short, highly branched signal receptive regions of the nerve cell. Convey incoming message toward cell bodies each nerve cell (neuron) has only one axon axon impulse generating and conducting region of neuron Whitish fatty protein layer that protects and electrically myelin sheath insulates the axon. Increases the speed of transmission of nerve impulses myelin sheath is only associated with axons, not dendrites what determines resting membrane potential balance of K+ and Na+ k+ leak permeability out of the cell Na+ leak permeability into the cell 3 types of ion channels chemically gated, voltage gated, mechanically gated chemically gated ion channels channel-linked receptors that open to let a specific ion pass in response to a ligand voltage-gated ion channels Channels that open or close in response to a change in the membrane potential. mechanically gated ion channels membrane ion channels that are opened or closed by deformation or stretch of the plasma membrane action potentials are also known as nerve impulses self-regenerating wave of electrochemical activity that al- action potential lows neurons to carry a signal over a distance. All or non phenomenon resting membrane potential - 70mV step one of action potential "Depolarization to Threshold" dendrites
GCU BIO 201 Exam 2 Test Questions and Answers Graded A+
step two of action potential Step Three of Action Potential step four of action potential A graded depolarization brings an area of excitable me- brane to threshold (-60mV) "Activation of Sodium Channels and Rapid Depolariza- tion"
- The voltage-regulated sodium channels open (sodium channel activation)
- Sodium ions, driven by electrical attraction and the chemical gradient, flood into the cell.
- The transmembrane potential goes from - 60 mV, the threshold level, toward +30 mV. "Inactivation of Sodium Channels and Activation of Potas- sium Channels"
- the voltage-regulated sodium channels close (sodium channel inactivation occurs) at +30 mV.
- The voltage-regulated potassium channels are now open, and the potassium ions dittuse out of the cell.
- Repolarization begins. "Return to Normal Permeability"
- The voltage regulated sodium channels regain their normal properties in 0.4-1.0 msec. The membrane is now capable of generating another action potential if a larger than normal stimulus is provided.
- The voltage regulated potassium channels begin clos- ing at - 70 mV. Because they do not all close at the same time, potassium loss continues and a temporary hyperpo- larization to approximately - 90 mV occurs.
- At the end of the relative refractory period, all volt-
GCU BIO 201 Exam 2 Test Questions and Answers Graded A+
regenerates easily if well nourished Microvilli increase absorption or secretion (in small intestine) cilia move fluids (in lungs and Fallopian tubes) basal lamina layers lamina lucida and lamina densa
- thin layer lamina lucida - secreted by epithelia
- barrier to proteins lamina densa thick fibers closer to connective tissue. Produced by con- nective tissue. Strength and filtration tight junctions between two cell membranes that prevents passage of water and solutes CAMs Cell Adhesion Molecules
- transmembrane proteins intracellular cement proteoglycans gap junctions small tunnels that allow rapid communications. Held to- gether by channel proteins. desmosomes helps handle mechanical stress. Ties cells together and allows bending and twisting
- Epithelia are replaced by division of germinative cells Repairing and Replacing Epithelia (stem cells)
- Near basal lamina classification of epithelium number of cell layers and shape of cells simple one layer stratified more than one layer shape of cells squamous, cuboidal, columnar squamous flattened
GCU BIO 201 Exam 2 Test Questions and Answers Graded A+
uct cell volume Cubodial cube shaped columnar column shaped gland one or more cells that make and secrete a particular prod- Ductless glands that empty their hormonal products di- rectly into the blood empty through ducts to the epithelial surface through ducts. Sweat tears, and oil glands. made in Golgi apparatus apocrine and merocrine glands not made in Golgi apparatus holocrine glands apocrine glands secrete products by shedding cytoplasm example of apocrine gland mammary gland merocrine glands secrete products by exocytosis in vesicles example of merocrine gland pancreas, most sweat glands, ans salivary glands holocrine glands fill up and rupture and die example of holocrine gland sebaceous gland connective tissue functions binding of organs, support, physical protection, immune protection, movement, storage, heat production, transport avascular without blood vessels well vascularized very rich blood supply extracellular matrix Non-living material that surrounds living cells. majority of mostly water along with adhesion proteins and polysac- charide molecules fibers produced by the cells exocrine glands endocrine glands ground substance
GCU BIO 201 Exam 2 Test Questions and Answers Graded A+
Where is fibrocartilage found? intervertebral discs and knee joint
- Fibroblasts
- Macrophages
- Adipocytes 8 cell types of areolar connective tissue
- Mesenchymal cells
- Melanocytes
- Mast cells
- Lymphocytes
- Neutrophil areolar connective tissue soft packaging material that cushions and protects body organs Where is areolar tissue found? dermis Fibroblasts found in connective tissue proper. Secrete proteins and hyalurornan Hyaluronan cellular cement Macrophages eat pathogens and damaged cells fixed macrophages stay in tissue free macrophages migrate Fat cells Each cell stores a single, large fat droplet mesenchymal cells stem cells that respond to injury or infection Types of mesenchymal cells fibroblasts and macrophages melanocytes Synthesize and store the brown pigment melanin stimulate inflammation after injury or infection
- release histamine and heparin basophils are mast cells carried by blood Lymphocytes specialized immune cells in lymphatic system mast cells Adipocytes
of fuel storage Example of lymphocytes plasma cells which produce antibodies Phagocytic blood cells respond to signals from macrophages and mast cells Example of phagocytic cells neutrophils and eosinophils functions of adipose tissue insulates the body, protects some organs, serves as a site white fat brown fat Most common Stores fat Absorbs shocks Slows heat loss (insulation) very little in adults
- more vascularized
- adipocytes have many mitochondria
- breaks down fat
- produces heat reticular connective tissue forms the stroma or internal "skeleton" of lymph nodes, the spleen, and other lymphoid organs blood connective tissue fluid extracellular matrix used to transport substances throughout the body. membranes Physical barriers, line or cover portions of the body
- an epithelial layer Membranes consist of 2 or 3 of the following - layer of areolar connective tissue
- layer of smooth muscle tissue 4 types of membranes mucous, serous, cutaneous, synovial line body cavities that are open to the exterior. Also in urinary and reproductive tracts To reduce friction To facilitate absorption and excretion mucous membrane Epithelial surfaces must be moist
cells are called cardiocytes cardiac involuntary muscle smooth muscle Surrounds hollow organs and tubes smooth one nucleus per cell smooth and cardiac can divide and regenerate smooth muscle Neurons and nerve support cells / Function is to send nervous tissue impulses to other areas of the body (irritability and con- ductivity) two types of nerve cells neurons and neuroglia neurons nerve cells perform electrical communication neuroglia support cells repair and supply nutrients to neurons skin cutaneous membrane skin derivatives sweat glands, oil glands, hair, nails protects deeper tissues from
- mechanical damage
- chemical damage first six skin functions second six skin functions
- bacterial damage
- thermal damage
- ultraviolet radiation
- desiccation
- protects underlying tissues and organs excretes salts, water, and organic wastes (glands)
- maintains body temp synthesize vitamin D
- stores lipids
- detects touch, pressure, pain, and temperature
hemidesmosomes composed of epithelial cells. Not vascular- nutrients and oxygen dittuse from capillaries in dermis stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale stratum germinativum has many basal cells. Is attached to basal lamina by Structures of Stratum Germinativum epidermal ridges and dermal papillae epidermal ridges fingerprints dermal papillae increase the area of the basal lamina and strengthen at- tachment between epidermis and dermis Cells of Stratum Germinativum merkel cells and melanocytes merkel cells found in hairless skin. scattered among cells of this layer. Respond to tough melanocytes Contain the pigment melanin Scattered throughout stratum basale stratum spinosum 8 - 10 layers, keratin causes spiny appearance, little mitosis Cells of Stratum Spinosum langerhans cells Langerhans cells stimulates a defense against microorganisms that man- age to get this deep in the skin stratum granulosum the grainy layer that stops dividing and starts producing keratin and keratohyalin A tough, fibrous protein Makes up hair and nails dense granules that cross-link keratin fibers. Promotes dehydration of cells stratum lucidum the clear layer only found in thick skin keratin epidermis keratohyalin layers of the epidermis
blister separation of the epidermal and dermal layers collagen and elastic fibers organized in parallel lines in lines of cleavage body, cuts in surgery are usually made parallel to these lines to help healing hypodermis subcutaneous layer hypodermis structure has more adipose than dermis hypodermis functions energy reservoir and thermal insulation. melanin brown hemoglobin red pheomelanin the pigment responsible for red hair. Have lower concen- trations of eumelanin homeostatic imbalance excessive sun exposure damages skin, causing clumping of elastin fibers freckles and moles local accumulations of melanin melanocytes stimulated when exposed to sunlight yellow to orange pigment found in certain plant products. carotene Accumulates in stratum core and in adipose of hypoder- mic Carotene can be converted to Vitamin A blue discoloration of the skin caused by a lack of adequate oxygen in the blood cyanosis
