IOS255 Comprehensive Exam Review Already Graded A

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

,Epithelial Tissue - ANSWER>>* Epithelia
* Glands (Exocrine & Endocrine)

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

3 Types of Muscles - ANSWER>>1. Skeletal muscle tissue
2. Cardiac muscle tissue
3. Smooth muscle tissue

Skeletal Muscle Tissue - ANSWER>>Moves the body

Cardiac Muscle Tissue - ANSWER>>Moves blood within the heart & through blood
vessels

Smooth Muscle Tissue - ANSWER>>* Moves fluids & solids along digestive tract
* Regulates diameter of small arteries, among other functions

Nervous Tissue - ANSWER>>* Specialized for conduction of electrical impulses
* 98% found in brain & spinal cord

Nervous Tissue - 2 Basic types of Cells - ANSWER>>1. Neurons
2. Neuroglia or glial cells (various supporting cells)

Cutaneous Membrane - ANSWER>>* Outer Epidermis
* Inner Dermis

Accessory Structures - ANSWER>>* Hairs
* Nails
* Exocrine glands (Sebaceous glands, Sweat glands)
* Sensory receptors & nerve fibers
* Arrector pili muscles
* Cutaneous plexus (network of blood vessels)

The Epidermis is Composed of Strata (layers) - ANSWER>>* Primary cell type in
epidermis is keratinocyte=produce keratin