IOS255 Comprehensive Exam Review Already Graded
A
Homeostasis - ANSWER>>* Presence of stable internal environment
* Failure to maintain homeostasis leads to illness or death
Homeostatic Regulation - ANSWER>>Physiological adjustment to preserve
homeostasis in variable environments
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BIOS255 Comprehensive Exam Review Already Graded
A
Homeostasis - ANSWER>>* Presence of stable internal environment
* Failure to maintain homeostasis leads to illness or death
Homeostatic Regulation - ANSWER>>Physiological adjustment to preserve
homeostasis in variable environments
Feedback - ANSWER>>Stimulation of a receptor triggers response that changes
environment at that receptor
Negative Feedback - ANSWER>>* Effector opposes or negates the original stimulus
* Minimizes change
* Primary mechanism of homeostatic regulation in the body
* Dynamic process: Set point varies with varying environments & activity levels
Negative Feedback Receptors - ANSWER>>Temperature receptors in skin & brain are
stimulated & send signals to the control center
Negative Feedback Control Center - ANSWER>>The temperature control center
received information from the two sets of temperature receptors & sends commands to
the effectors
Negative Feedback Effectors - ANSWER>>Sweat glands & smooth muscle in the walls
of blood vessels supplying the skin respond
Positive Feedback - ANSWER>>* Stimulus produces a response that exaggerates or
enhances the original change (rather than opposing it)
* Tends to produce extreme responses
* Does not restore homeostasis
Positive Feedback Loop - ANSWER>>* Escalating cycle
* Typically occurs when a potentially dangerous or stressful process must be completed
quickly before the body can restore homeostasis
Steps of Positive Feedback in Blood Clotting - ANSWER>>1. Damage to cells in the
blood vessel wall releases chemicals that begin the process of blood clotting
2. The chemicals start chain reactions in which cells, cell fragments, & soluble proteins
in the blood begin to form a clot
3. As clotting continues, each step releases chemicals that further accelerate the
process
4. This escalating process is a positive feedback loop that ends with the formation of a
blood clot, which patches the vessel wall & stops the bleeding
Functions of Epithelial Tissue - ANSWER>>* Provide physical protection
* Control permeability
* Provide sensation
* Produce specialized secretions
Characteristic of Epithelial Tissue - ANSWER>>* Specialized contacts with other cells
* Polarity (different ends of cell do different things)
* Avascularity (NO blood supply)
* Regeneration (can divide to make new cells)
* Cellularity (lots of cells in close contact)
Characteristics of Epithelial Tissue: Specialized Contacts - ANSWER>>Epithelial cells
are held close together by cell junctions
Features of Epithelial Tissue - ANSWER>>* Surfaces: Apical surface-Faces exterior of
body or internal space; Base- Attached to underlying tissues
* Polarity: Refers to structural differences between exposed & attached surfaces
Connective tissue overview - ANSWER>>* Varies widely in appearance & function
(Found throughout the body, but never exposed to surface)
* Ranges from highly vascular to avascular
* Many contain sensory receptors that detect pain, pressure, temperature, & other
stimuli
3 basic components shared by connective tissues - ANSWER>>1. Specialized cells
2. Extracellular protein fibers
3. Fluid called ground substance
Extracellular Protein Fibers - Reticular Fibers - ANSWER>>Strong & form branching
network
Extracellular Protein Fibers - Collagen Fibers - ANSWER>>Thick, very strong
Extracellular Protein Fibers - Elastic Fibers - ANSWER>>Slender, very stretchy
Connective Tissue Ground Substance - ANSWER>>* Clear & colorless
* Viscous (syrupy) due to presence of proteoglycans & glycoproteins
* Allows substances to travel between blood capillaries & cells
Cartilage overview - ANSWER>>* Matrix is a firm gel containing chondroitin sulfates
(cartilage), polysaccharide dervatives
* Only 1 type of cell (chondrocyte)
* Avascular
, Osseous Tissue (Bone Tissue) - ANSWER>>* Connective tissue with solid, crystalline
matrix
*Small volume of ground substance
* 2/3 of matrix is calcium salts (provide strength)
*Mostly calcium phosphate
* Some calcium carbonate
* Many collagen fibers (provide flexibility)
* Strong, somewhat flexible, resistane to shattering
Muscle Tissue - ANSWER>>* Specialized for contraction to cause movement
* Movement of the body
* Movement of blood around the cardiovascular system
* Movement of materials along the digestive tract
The Epidermis is Composed of Strata (layers) - ANSWER>>* Primary cell type in
epidermis is keratinocyte=produce keratin
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