Introdction To Basic Tissue Types Muscle And Nervous

Question 1

Muscle tissue

Answer 1

Responsible for generating movement of animal body and its parts, including musculoskeletal system, visceral organs, heart

Question 2

Characteristics of muscle cells

Answer 2

Muscle cells also called myocytes, large amounts of contractile proteins actin and myosin

Question 3

Myofibril

Answer 3

Structural and functional subunits of muscle cells, composed of actin and myosin myofilaments organized in specific and repetitive manner

Question 4

Classification of muscle

Answer 4

classified according to appearance of contractile cells
2 principle types- smooth and striated
Can differentiate based on size and shape of cell, number, shape, and location of nuclei within cell
All muscle cells regardless of type are surrounded by external lamina that is analogous to basement membrane of epithelial tissue

Question 5

Striated muscle cells

Answer 5

Exhibit cross striations at light microscopic level by myofilaments are in parallel arrays in register with each other
Subdivided into
Skeletal and cardiac based on function and location

Question 6

Smooth muscle

Answer 6

Myofilaments are not organized in parallel arrays and it therefore does not have striated appearance

Question 7

Comparison of three muscle types

Answer 7

Shape Number, shape, and location nuclei
Skeletal Cylindrical Multiple, flat, peripheral
Cardiac Branched. Single, block like, central
Smooth. Fusiform. Single, spindle-or corkscrew-shaped, central

Question 8

Organization skeletal muscle

Answer 8

Striated muscle fibers held together by connective tissue, muscle fiber is multinuclearted syncytium formed by fusion of small individual myoblasts during development; in cross section skeletal muscle fibers have polygonal shape, long axes are in the direction in which the contract
Associated connective tissue
Endomysium, perimysium, epimysim

Question 9

Endomysium

Answer 9

Thin delicate layer of reticular fibers that immediately surrounds individual muscle fibers

Question 10

Perimysium

Answer 10

Thicker layer that surrounds group of fibers forming bundle (fascicle)

Question 11

Epimysium

Answer 11

Forms dense sheath surrounding collection of fascicles which forms a muscle

Question 12

Organization of Cardiac muscle

Answer 12

Cardiac muscle also called myocardium. Appears striated bc myofilaments organized in same manner as skeletal muscle, fibers are not multinucleated syncytium like in skeletal muscle but rather multiple cells arrayed end to end; cells attach to each other via intercalated discs; can form branched fiber via joining of two or more cells

Question 13

Smooth muscle

Answer 13

Smooth muscle generally in sheets or bundles of elongated fusiform cells with tapered ends; cytoplasm will stain envelope with eosin

Question 14

Sensory component of nervous system

Answer 14

Collects info from external environment and from within body

Question 15

Motor component of nervous tissue

Answer 15

Controls activity of muscles, organs, and even individual cells

Question 16

Anatomical division of nervous system

Answer 16

CNS- brain and spinal chord

PNS- nerves that conduct impulses to and from brain and spinal chord

Question 17

Cell types of nervous tissue

Answer 17

Neurons and neuroglia ( supporting cells)
Neuron- functional unit of nervous system, relieve stimuli from other cells and conduct electrical impulses accordingly
Neuroglia- non conducting cells, located near neurons, functions: physical support, electrical insulation, facilitation of repair, regulation internal fluid environment in CNS, clearance neurotransmitters metabolic exchange between vascular system and neurons

Question 18

Axon

Answer 18

Transmits impulses away from cell body to synapse which makes contact with another neuron or an effector cell (muscle cell or glandular epithelial cell); in PNS all neurons are enveloped in Schwann cells providing structural and metabolic support. Non-myelinated axons enveloped by cytoplasm of Schwann cells. Myelinated axons are wrapped in myelin sheath consisting of variable number of concentric layer of Schwann cell plasma membrane. In CNS axon myelinated by oligodendrocytes
When viewed via light microscopy axons appear wavy bc need extra length to withstand stretching forces

Question 19

Dendrites

Answer 19

Transmit impulses toward the cell body; receptors that recieve impulses from other neurons or from external environment, Nissl bodies, free ribosomes, and occasionally Golgi apparatus will extend into dendrites (NEVER axon)

Question 20

Cell body of neuron

Answer 20

Contains nucleus and organelles, nucleus is large and euchromatin with prominent nucleus (bc cell makes a lot of protein), abundant free ribosomes and rough ER, mitochondria (numerous), large Golgi apparatus, lysosomes, transport vesicles, cytoskeletal elements

Question 21

Nissl bodies

Answer 21

When viewing neuron cell body by light microscopy the abundant ribosomal constant appears as small intensely basophillic bodies called Nissl bodies, each Nissl body corresponds to a stack of rER

Question 22

Axon hillock

Answer 22

Junction of axon with cell body, lacks large organelles, good way to distinguish between axon and dendrites

Question 23

Ganglia

Answer 23

Groups of nerve cells outside of CNS. Ganglion consists of cell bodies of either sensory or motor neurons NEVER both

Question 24

Nerves

Answer 24

Groups of axonal processes (aka nerve fibers) travel together in anatomical structure known as nerve; Nerves can be sensory motor or mixed

Question 25

Peripheral nerves

Answer 25

Held together by connective tissue in manner similar to skeletal muscle Endoneurium- composed of loose connective tissue surrounds each individual fiber Perineurium- surrounds fascicles (bundles of fibers) Epineurium- dense irregular connective tissue that surrounds entire nerve and fills in spaces between nerve fascicles

Question 26

Questions for identifying tissues

Answer 26

1. Are the cells on a surface 2. Are the cells in contact with their neighbors or are the separated from each other by an intervening substance 3. Do the cells belong to a group with specialized functional (and structural) properties such as nerve of muscle

Question 27

Autonomic ganglia

Answer 27

Clusters of neurons located along autonomic pathways, contain autonomic motor neurons 3 major categlories Sympathetic trunk ganglia, ganglia in head, abdomen, and pelvic cavity, and Terminal Ganglia

Question 28

Sympathetic trunk ganglia

Answer 28

Located ventrolaterally to vertebral bodies along sympathetic trunk, connected to spinal nerves by communicating branches, generally segmental other than Cranial Cervical Ganglion- multiple fused cervical ganglia at caudal skull base Middle cervical ganglion- multiple fused cervical ganglia at thoracic inlet Cervicothoracic ganglion- caudal cervical ganglia fused with first 2-3 thoracic ganglia

Question 29

Ganglia located in head abdomen and pelvic cavity

Answer 29

Ciliary ganglia of head (parasympathetic), celiacemosenteric and caudal mesenteric ganglia of abdomen (sympathetic), pelvic ganglia (sympathetic and parasympathetic)

Question 30

Terminal ganglia

Answer 30

Microscopic clusters of neurons located within target tissue, associated with vagus and pelvic nerves, involved in parasympathetic function

Question 31

Vertebral nerve

Answer 31

Continues cranially from cervicothoracic ganglion to supply sympathetic autonomic innervation of skin and muscles of the neck, travels with vertebral artery into transverse foramina of cervical vertebrea Communicating branches from vertebral nerve join each cervical spinal nerve to provide sympathetic innervation to muscles and skin supplied by that spinal nerve, NO SYMPATHETIC GANGLIA IN VERTEBRAL NERVE bc axons making up vertebral nerve have cell bodies (from sympathetic neurons) in cervicothoracic ganglion

Question 32

Sensory pathways

Answer 32

Carrying information from tissues to the CNS, somatic and visceral afferent pathways

Question 33

Motor pathways

Answer 33

Carrying commands from the CNS to muscles and glands, somatic and visceral efferent pathways ** Visceral efferent subdivides into sympathetic and parasympathetic

Question 34

Visceral efferent

Answer 34

Motor pathway (ANS), smooth muscle, cardiac muscle, glands, split into parasympathetic (vegetative functions) and sympathetic (fight of flight)

Question 35

Somatic afferent

Answer 35

Sensory, skin, bones, joints, skeletal muscles

Question 36

Visceral afferent

Answer 36

Internal organs, sensory

Question 37

Somatic efferent

Answer 37

Motor skeletal muscles

Question 38

Visceral efferent

Answer 38

Motor pathway, ANS, sympathetic (fight for flight), parasympathetic (vegetative functions)

Question 39

Visceral and somatic information with in CNS

Answer 39

Will be integrated ie stepping on a tack produces sympathetic (Visceral efferent) response of increased heart rate and somatic efferent response of pulling foot away

Question 40

Somatic efferent pathways

Answer 40

Consist of one neuron from CNS to target muscle, these are called lower motor neurons or somatic efferent neurons, most skeletal muscle under voluntary control so this is referred to as voluntary muscle (though not all under voluntary control)

Question 41

Location of cell bodies of LMN that control skeletal muscles of body

Answer 41

Somatic efferent neurons ie LMN are in Ventral horn of spinal cord, axons exit spinal cord via ventral root then spinal nerve, exit dorsal branch for epaxial muscle and ventral branch for hypaxial muscles Synaptic terminal of LMNs forms specialized synapse on muscle fibers called neuromuscular junction where neurotransmitters are released from axon terminal leading to muscle fiber contraction

Question 42

Location of cell bodies that control skeletal muscles of head

Answer 42

Brainstem axons exit brainstem and travel in cranial nerves

Question 43

Phrenic nerve motor pathway

Answer 43

Phrenic nerve is somatic so LMN cell bodies are in ventral horn of spinal chord, segments C5C6C7 (keep you from going to heaven), axons exit each segment via ventral root and enter spinal nerve then ventral branches, leave ventral branches to merge and form phrenic nerve (bilaterally), axons of phrenic nerve terminate in neuromuscular junctions of muscle fibers of diaphragm