Ch 4 Flashcards
what are tissues?
groups of cells organized to perform specific functions
Tissues, through the collaborative efforts of their individual cells, are responsible for ________
maintaining body functions
Cells within tissues are connected to each other by specialized _________ and communicate with each other via __________.
- junctions
- intercellular junctions
There are only four basic tissue types:
- epithelium
- connective
- muscle
- nerve
The definition of epithelial and connective tissue is primarily __________;
for muscle and nerve tissue, it is primarily ____________.
- morphologic
- functional
what is epithelium characterized by?
close cell apposition and presence at a free surface.
Epithelial cells are always ______ with one another and joined by ____________.
- contiguous
- cell-to-cell junctions
where is epithelial tissue?
it covers body surfaces, lines body cavities and tubes, and forms glands
what are classifications of epithelium based on?
cell shape and number of cell layers
what are the different cell shapes?
squamous, cuboidal, columnar
what are the different cell layers called?
simple or stratified
what is simple epithelia
one layer thick
ex: simple cuboidal and simple columnar epithelia.
what is stratified epithelia?
contains multiple layers of cells
ex: stratified squamous epithelium.
The free surface of the epithelium may exhibit special structural surface modifications such as ___________
microvilli, stereocilia, or cilia
Epithelia rest on the ___________, the structural attachment site for overlying epithelial cells and underlying _________.
- basal lamina
- connective tissue
Epithelium is _________; nutrients are obtained by _____________ from underlying tissues
- avascular
- absorption or diffusion
what is connective tissue characterized by?
its extracellular matrix
Connective tissue cells are _________ from one another.
separated
Connective tissue___________ and __________ other basic tissues.
- underlies
- supports
what is connective tissue classified based on?
- the content of its extracellular matrix
- the characteristics of its cells.
what are the three types of connective tissue?
- embryonic connective tissue
- connective tissue proper (loose and dense)
- specialized connective tissues
what does loose connective tissue contain?
loosely arranged collagen fibers and numerous cells.
what does dense connective tissue contain?
more numerous and densely packed collagen fibers with sparse cells.
what are examples of specialized connective tissues?
- bone
- cartilage
- blood
- adipose tissue
The ___________ rather than cells characterizes most connective tissues, but not ___________ tissue.
- extracellular material
- adipose
what is muscle tissue categorized by?
ability of its cells to contract
what are the contractile proteins that muscle cells contain large amounts of?
actin and myosin
what is muscle tissue classified into?
- skeletal
- cardiac
- smooth
what do skeletal and cardiac muscle cells exhibit?
cross-striations
Smooth muscle cells ______ exhibit cross-striations.
do not
The ______ array of muscle fibers allows for collective effort in performing their function.
- parallel
what does nerve tissue do?
Receives, transmits, and integrates information from inside and outside the body.
what is nerve tissue composed of?
- nerve cells (neurons)
- supporting cells
what are neurons specialized for?
transmitting electrical impulses
what does a neuron consist of?
- cell body
- a single long axon
- multiple dendrites.
The axon terminates at a neuronal junction called a ________ at which electrical impulses are transferred from one cell to the next by secretion of ________________.
- synapse
- neuromediators (neurotransmitters)
what do neurons interact with?
- other nerve cells
- cells of the epithelia
- cells of muscle
what are supporting cells in the central nervous system (CNS) called
neuroglial cells
what are supporting cells in the peripheral nervous system (PNS) called
Schwann cells and satellite cells.
what are the functions of nerve tissue?
- insulation (myelin sheath)
- active phagocytosis to remove cellular debris
- bb barrier in CNS
- retain absorptive and secretory functions through ependymal cells
what does the myelin sheath do?
insulates and speeds conduction in certain types of neurons
what do ependymal cells and cells of the choroid plexus in CNS do?
retain the absorptive and secretory functions characteristic of epithelial cells
In a standard hematoxylin and eosin (H&E)-stained section, nerve tissue can be observed in the following ways:
nerves appear as collections of……
neuronal processes (axons and dendrites) and their supporting cells.
neuronal processed are most often seen in __________ sections within __________ tissue.
- longitudinal or cross
- loose connective
The neuronal processes are thread-like and may be myelinated, and are held together by connective tissue.
in cross sections, how do axons appear?
as small, dot-like structures
where are Nerve cell bodies in the peripheral nervous system (PNS), including the autonomic nervous system (ANS) found in?
ganglia
what is ganglia?
aggregations of nerve cell bodies.
what are nerve cell bodies surrounded by?
satellite cells
what are the three term layers?
- ectoderm
- mesoderm
- endoderm.
what is the ectoderm?
the outermost germ layer and gives rise to the
- epidermis and its derivatives
- nervous system
- and other structures
what does the ectoderm give rise to?
- epidermis
- cornea and lens epithelia
- enamel organ and enamel of teeth
- adenohypophysis (anterior petuitary)
- mucosa or oral cavity and anal canal
what does the neuroectoderm give rise to?
- neural tube
- neural crest
what does the neural tube give rise to?
- components of the CNS
- ependyma (epithelium lining the cavities of the brain and spinal cord)
- pineal body
- posterior lobe of the pituitary gland (neurohypophysis)
- sensory epithelium of the eye, ear, and nose
what does the neural crest give rise to?
- components of the PNS (cranial, spinal, and autonomic ganglia; peripheral nerves; and Schwann cells)
- glial cells (oligodendrocytes and astrocytes)
- chromaffin (medullary) cells of the adrenal gland
- enteroendocrine cells, also called amine precursor uptake and decarboxylation (APUD) system cells of the diffuse neuroendocrine system
- melanoblasts, the precursors of melanocytes
- the mesenchyme of the head and its derivatives (such as pharyngeal arches that contain muscles, connective tissue, nerves, and vessels)
- odontoblasts
- corneal and vascular endothelium.
what does the mesoderm (middle layer) give rise to?
- connective tissue
- striated muscles and smooth muscles
- heart, blood vessels, and lymphatic vessels, including their endothelial lining
- spleen
- kidneys and gonads
- mesothelium
- adrenal cortex
what is the connective tissue that the mesoderm gives rise to?
(mesenchyme), connective tissue proper (loose and dense connective tissue)
specialized connective tissues (cartilage, bone, adipose tissue, blood and hemopoietic tissue, and lymphatic tissue)
what is the mesothelium?
the epithelium lining the pericardial, pleural, and peritoneal cavities
what is the endoderm?
the innermost germ layer and gives rise to the
- epithelial linings of the digestive and respiratory systems and other structures.
what does the endoderm give rise to?
- the alimentary canal epithelium
- extramural digestive gland epithelium
- epithelium of the urinary bladder and most of the urethra
- respiratory system epithelium
- thyroid, parathyroid, and thymus gland epithelial components
- parenchyma of the tonsils
- lining epithelium of the tympanic cavity and auditory (Eustachian) tubes
what are examples of the extramural digestive gland epithelium?
the liver, pancreas, and gallbladder
what are ovarian teratomas?
tumors that may contain cells from all three germ layers.
how do teratomas arise?
from pluripotential stem cells, primarily in the gonads.
Ovarian teratomas are usually ______, whereas testicular teratomas are often _________.
- benign
- malignant
what do mature teratomas of the ovary may contain?
mature tissues arranged in an unorganized manner.
what is recognition of the tissues based on?
- the presence of specific components within cells
- specific cellular relationships.
It is important to recognize ________ of cells as tissues and to determine their ________.
- aggregates
- special characteristics
