Bio 255 Lab Week 3 Questions and Answers

Bio 255 Lab Week 3 Questions and Answers areolar connective tissue Binds and cushions organs and skin By volume, mostly viscous ground substance Elastic properties from loosely organized protein fibers Highly vascularized adipose tissue Stores triglycerides for a future source of energy (fat cells) Insulation, protects vital organs Only connective tissue with more cells than matrix reticular connective tissue Reticular fibers provide framework (stroma) of organs Found in liver, spleen lymph nodes, bone marrow, etc. dense regular connective tissue Tightly packed collagen fibers running parallel Much strength against force in one direction Ligaments, tendons, aponeuroses Dense Irregular CT Fibers run in several different directions Strength against force in many directions Found in dermis of skin, supporting layers of cartilage and bone, capsules of organs elastic connective tissue Elastic fibers and collagen fibers Allow stretch under force and recoil to allow original shape Found in vocal cords, walls of arteries hyaline cartilage Withstands stretch and compression Flexible and resilient Found in embryonic skeleton, articular cartilage, trachea, larynx, etc. Fibrocartilage Durable; provides strength while allowing compression Many protein fibers, sparse ground substance Found in intervertebral discs, pubic symphysis, menisci of knee joints elastic cartilage Extremely resilient and flexible Lots of elastic fibers that are highly branched Found in the epiglottis, external ear bone connective tissue Calcified matrix with collagen Provides support and protection Mineral storage Blood cell formation blood connective tissue Blood cells in a liquid matrix (plasma) Transport of respiratory gases, nutrients, wastes, etc. skeletal muscle tissue • Very long and cylindrical parallel fibers with perpendicular filaments (striation) Function: Connects to and moves skeleton cardiac muscle tissue • Long fibers that can branch (Yshape) with perpendicular striation, intercalated discs Function: Forms the walls of the heart, moves blood (involuntary) smooth muscle tissue • Spindle-shaped cells that lack striations Function: Involuntary muscle contraction, propels substances through hollow organs nervous tissue Cells are neurons (have axon and dendrites) and neuroglia (support neurons, greatly outnumber neurons) Function: Control and communicate with other cells apocrine sweat glands produce true sweat plus fatty substances and proteins; found in the axillary (armpit) and genital areas of the body after puberty arrector pili muscle The small, involuntary muscle in the base of the hair follicle. Tactile corpuscles (Meissner's corpuscles) sensitive to fine touch; in the papillary region of dermis dermal papilla extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis dermis middle layer of skin eccrine sweat glands (merocrine) widely distributed and produce watery perspiration as a means of regulating body temp. epidermal ridge this can help increase friction for improved grasping ability and provides the basis for fingerprints and footprints epidermis outermost layer of skin hair follicle a small tubular cavity containing the root of a hair hair root The part of the hair contained within the follicle, below the surface of the scalp. hair shaft The portion of hair that projects above the epidermis subcutaneous layer (hypodermis) Beneath dermis; insulating layer Areolar and adipose connective tissue Not considered part of the skin Contains blood vessels that supply skin Lamellated corpuscles (Pacinian corpuscles) Sensitive to deep pressure Fast-adapting receptors Most sensitive to pulsing or high-frequency vibrating stimuli papillary region the superficial area of the dermis composed of areolar connective tissue, dermal papillae, Meissner corpuscles of touch, and free nerve endings reticular region the deeper part of the dermis consisting of dense irregular connective tissue containing bundles of collagen fibers and some elastic fibers sebaceous glands secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis sweat pore the surface opening of a sweat duct dead keratinocytes Make up 90% of the cells of the epidermis keratinocyte cell that produces keratin and is the most predominant type of cell found in the epidermis lamellar granules contain a water-resistant glycolipid that is spewed into the extracellular spacel; found in stratum granulosum Epidermal dendritic cells (Langerhans cells) -Often present in stratum spinosum and stratum granulosum -Immune cells that help initiate immune response -Responsive to pathogens and epidermal cancer cells melanocyte cell in the basal layer that gives color to the skin tactile cells (merkel cells) sensory touch receptors sensory neurons neurons that carry incoming information from the sensory receptors to the brain and spinal cord stratum basale the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells stratum corneum outermost layer of the epidermis, which consists of flattened, keratinized cells stratum granulosum a layer of the epidermis that marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata stratum lucidum a layer of the epidermis found only in the thick skin of the fingers, palms, and soles