Ch 6b: Muscle Tissue and Nervous Tissue

Question 1

what are the three types of muscle tissue

Answer 1

1. skeletal
2. cardiac
3. smooth

Question 2

what is the structure of skeletal muscle

Answer 2

long, multi-nucleated cells (fibers); striated ( sarcomeres arranged in bands ); cells run in parallel direction

Question 3

what is the function of skeletal muscle

Answer 3

voluntary contractions

Question 4

what is the location of skeletal muscle

Answer 4

attach to bone via tendons; attach to axial and appendicular divisions of the skeleton

Question 5

what is the structure of cardiac muscle

Answer 5

small, mono-nucleated cells; striated ( sarcomeres arranged in bands ); contain intercalated discs (junction between cells and allows spread of nervous impulse); branching of cells

Question 6

what is the function of cardiac muscle

Answer 6

involuntary contractions

Question 7

what is the location of cardiac muscle

Answer 7

heart

Question 8

what is the structure of smooth muscle

Answer 8

small, mono-nucleated cells; non-striated ( no sarcomeres or bands present ); cells flow into each other

Question 9

what is the function of smooth muscle

Answer 9

involuntary contractions

Question 10

what is the location of smooth muscle

Answer 10

walls of blood vessels(circulation of blood); and viscera (except heart)

Question 11

what are the three parts of a neuron

Answer 11

1. dendrite
2. cell body (soma)
3. axon

Question 12

dendrite

Answer 12

one or more; pick up nerve impulse (action potential) and send to cell body

Question 13

cell body (soma)

Answer 13

one; contains the nucleus; translates the incoming impulse (message)

Question 14

axon

Answer 14

one; longest part of neuron; picks up translated message from the cell body and sends to target (effector organ)

Question 15

effector organ

Answer 15

can be another neuron; gland; or muscle

Question 16

glial cells (neuroglia)

Answer 16

these are supporting cells; do not conduct nerve impulses; are found in both the Central Nervous System ( Brain and Spinal Cord ) and the Peripheral Nervous System ( outside of brain & spinal cord )

Question 17

tissue growth

Answer 17

1. Tissues grow because their cells increase in number or size.
2. Most embryonic or childhood growth occurs by hyperplasia (tissue growth by multiplication).
3. Skeletal muscle and adipose tissue grow through hypertrophy (the enlargement of pre-existing cells).
4. Neoplasia (is the development of a tumor, whether benign or malignant, and is composed of abnormal, nonfunctional tissue).

Question 18

tissue development

Answer 18

1. Embryonic Tissue undergoes differentiation
2. Epithelia can sometimes exhibit metaplasia
3. stem cells

Question 19

differentiation

Answer 19

(the development of a more specialized form and function); i.e. the differentiation of mesenchyme to muscle

Question 20

metaplasia

Answer 20

(a change from one type of mature tissue to another); i.e. pre-puberty vaginal epithelia is simple cuboidal, and at puberty changes to stratified squamous

Question 21

stem cells

Answer 21

Are undifferentiated cells that are not yet performing any specialized function, but have the potential to differentiate into one or more types of mature, functional cells

Question 22

embryonic stem cells

Answer 22

1. Compose the early embryo
2. Totipotent stem cells – have the potential to develop into any type of fully differentiated human cell, not only cells of the later embryonic, fetal, or adult body, but also cells of the temporary structures of pregnancy, such as the placenta and amniotic sac; have unlimited developmental plasticity
3. Pluripotent stem cells – have the potential to develop into any cell type of the embryo, but not into the accessory organs of pregnancy; have somewhat limited developmental plasticity

Question 23

adult stem cells

Answer 23

1. Occur in small numbers in mature organs and tissues throughout a person’s life.
2. An adult stem cell divides mitotically; one of the daughter cells remains a stem cell, and the other one differentiates into a mature specialized cell

3 .Multipotent stem cells – able to develop into two or more different cell lines; some bone marrow stem cells can give rise to all types of blood cells

4. Unipotent stem cells – can produce only one mature cell type; cells that give rise to egg and sperm cells

Question 24

what are the two ways damaged tissue can repair

Answer 24

1. regeneration

2. fibrosis

Question 25

regeneration

Answer 25

the replacement of dead or damaged cells by the same type of cells as before; restores normal function to the organ; most skin injuries heal by regeneration

Question 26

fibrosis

Answer 26

the replacement of damaged tissue with scar tissue, composed mainly of collagen produced by fibroblasts; scar tissue helps hold the organ together, but it does not restore normal function; scarring of lungs after tuberculosis infection

Question 27

atrophy

Answer 27

is the shrinkage of a tissue through a loss in cell size or number; it results from normal aging (senile atrophy) and lack of use of an organ (disuse atrophy)

Question 28

necrosis

Answer 28

is premature, pathological tissue death due to trauma, toxins, or infection;

Question 29

infarction

Answer 29

is the sudden death of tissue that occurs when its blood supply is cut off;

Question 30

gangrene

Answer 30

is any tissue necrosis resulting from an insufficient blood supply, usually involving infection

Question 31

apoptosis (programmed cell death)

Answer 31

is the normal death of cells that have completed their function and best serve the body by dying and getting out of the way; cells shrink and are quickly phagocytized by macrophages; every cell has a built in “suicide program”

Question 32

what are the two possible suicide program mechanism

Answer 32

1. Extracellular suicide signal binds to a receptor protein in the plasma membrane known as Fas Fas activates intracellular enzymes that destroy the cell; includes an endonuclease which chops up the DNA, and a protease which destroys the cellular proteins 2. Cells seem to undergo apoptosis automatically if they stop receiving growth factors from other cells