Bio 301 Lab 3

Front 1

Contractility

Back 1

Property that enables muscle cells to change shape

Front 2

Skeletal muscle

Back 2

Voluntary muscle; contraction is under voluntary control; attached to the skeleton

Front 3

Muscle fibers

Back 3

Individual muscle cells; metabolically active

Front 4

Sarcolemma

Back 4

Plasma membrane of the muscle cell

Front 5

Myofibrils

Back 5

Slender, rod-like structures packed inside the muscle cell; composed of overlapping thick and thin filaments

Front 6

Cross-striations

Back 6

Alternating light and dark sections in longitudinal sections of muscle due to the thick and thin filaments of Myofibrils

Front 7

Myoblast

Back 7

Embryonic cell that becomes a cell of muscle fiber

Front 8

Cardiac muscle

Back 8

Involuntary control; forms the heart muscle; exhibits branching; each cell has one or two centrally located nucleus

Front 9

Intercalated disks

Back 9

Darkly stained transverse lines between to cardiac cells, usually in stepwise formation; contain demos omens and gap junctions

Front 10

Autorhythmic

Back 10

Cells that undergo spontaneous electrical excitation which then spreads throughout the heart and triggers a contraction

Front 11

Smooth muscle

Back 11

involuntary control; Forms the muscular portion of visceral organs, surrounds larger blood vessels, and attaches to hair follicles

Front 12

Peristaltic waves

Back 12

Spontaneous contractions in smooth muscle

Front 13

Neuron

Back 13

Cells responsible for sensing, thinking, controlling muscle activity, and regulating glandular secretions; don't repair easily

Front 14

Synapse

Back 14

The site of functional contact between two neurons or a neuron and an effector cell

Front 15

Neurotransmitter

Back 15

Substance the mediates the transfer of infirmation across a synapse

Front 16

Soma or perikaryon

Back 16

Cell body of a neuron; contains a nucleus surrounded by cytoplasm and contains typical organelles along with nissl bodies and neurofibrils

Front 17

Nissl bodies

Back 17

Clusters of rough endoplasmic reticulum where protein synthesis occurs

Front 18

Neurofibrils

Back 18

Intermediate filaments that form the cytoskeleton of the cell; provide shape and support

Front 19

Dendrites

Back 19

receiving/input portion of the neuron

Front 20

axon

Back 20

conducts nerve impulses toward another neuron, muscle fiber, or gland cell

Front 21

axon hillock

Back 21

cone-shaped elevation where the axon connects to the cell body

Front 22

axon collaterals

Back 22

side branches along the axon; typically at a right angle

Front 23

nerve fiber

Back 23

general term for any neuronal process

Front 24

nerve

Back 24

bundle of many nerve fibers that course along the same path in the PNS; contain both sensory and motor axon bundles

Front 25

neuroglia

Back 25

the neuron of the CNS; smaller than neurons and much more numerous; fill spaces formerly occupied by neurons after cases of trauma

Front 26

astrocytes

Back 26

star-shaped cells; metabolize neurotransmitters; maintain proper K+ balance, participate in brain development; provide a link between neurons and blood vessels

Front 27

oligodendrocytes

Back 27

produce myelin sheaths around axons in the CNS; spirals around multiple portions of the axon; nodes of ranvier are less present

Front 28

microglia

Back 28

small, phagocytic neuroglia; protect CNS from disease by enveloping microbes and clearing away debris

Front 29

ependymal cells

Back 29

squamous to columnar in shape; line brain ventricles and the central canal of the spinal cord

Front 30

schwann cells

Back 30

produce myelin sheaths around PNS neurons; spirals many times around a section of axon; (results in up to 100 layers of cell membrane)

Front 31

myelin sheath

Back 31

multilayered lipid and protein covering; electrically insulates the axon of a neuron and increases the speed of nerve impulse conduction

Front 32

epidermis

Back 32

outer epithelial layer; contains 4 principal cell types; protects from abrasion and dehydration

Front 33

dermis

Back 33

highly vascularized layer underneath the epidermis; supports surface epithelia; made up of elastic and collagen fibers; contains hair follicles and sweat glands as well as nerves and nerve endings

Front 34

keratinocytes

Back 34

produce a protein called keratin

Front 35

keratin

Back 35

substance that helps protect skin and underlying tissues from light and heat, microbes, and chemicals

Front 36

melanocytes

Back 36

produce the pigment melanin

Front 37

melanin

Back 37

brown-black pigment; absorbs UV light; creates a protective veil over keratinocyte nuclei

Front 38

langerhans cell

Back 38

cells that arise from bone marrow; interact with T cells in immune responses

Front 39

merkel cell

Back 39

attached to keratinocytes by desmosomes; thought to function in the sensation of touch b/c they touch the tactile disk of a neuron

Front 40

stratum basale

Back 40

single layer of cuboidal to columnar cells; contains stem cells and melanocytes; has the ability to constantly create new cells

Front 41

stratum spinosum

Back 41

composed of many sided cells that fit closely together; 8-10 layers

Front 42

stratum granulosum

Back 42

3-5 layers of flattened cells; nuclei are in various stages of degeneration; develop keratohyalin (precursor to keratin)

Front 43

stratum lucidum

Back 43

only found in thick skin of fingertips, palms, and soles; 3-5 layers of clear, dead cells containing intermediate substance

Front 44

stratum corneum

Back 44

25-30 layers of dead cells filled with keratin; continually replaced by cells from deeper strata

Front 45

keratinization

Back 45

cells newly formed in the stratum basale undergo a developmental process as they are pushed to the surface; as they relocate, they accumulate keratin

Front 46

callus

Back 46

abnormal thickening of the epidermis through constant exposure to friction or pressure

Front 47

arrector pili muscles

Back 47

diagonal muscles that contract to rotate hair follicles; produces good bumps

Front 48

sebaceous glands

Back 48

found around hair follicles; pours sebum into hair follicle; sebum spread over skin, coats hair, and waterproofs skin

Front 49

eccrine sweat gland

Back 49

most common type of gland; secretory portion located deep in the dermis

Front 50

apocrine sweat glands

Back 50

function after puberty; stimulated by emotional stress and sexual excitement