Download Specialized Tissue in Animals

Specialized Tissue in Animals
Nerves
• Nervous tissue – the tissue responsible for regulating, controlling
and transmitting signals throughout the body
• Neuron – a nerve cell that processes and transmits information
through signals
• Dendrites – a branched appendage attached to a neuron's cell body that
receives and transmits impulses
• Axon – a long tail extending away from a cell body through which
impulses are conducted
• Synapse – the point where the axon from one neuron meets the dendrites
of another neuron; the point through which a signal can be passed
• Action potentials – the electrical signals that transmit information across
neurons away from a cell body
• Resting potential – the negative intracellular charge of a neuron while at rest
• Maintained by gated ion channels
• More positive ions outside and more negative ions inside
• Neuron stimulation opens gated ion channels
• Depolarization – a change in a cell's membrane potentially caused by an
increase in positive ions in the neuron
• Threshold – the ion gradient of a neuron above which an action potential will
be produced
• Action potentials are an all-or-nothing event
Biology 17.2 – Specialized Tissue in Animals
Specialized Tissue in Animals
Muscle
• Muscle tissue – the tissue that composes muscles and contracts to create movement
• Muscles that are not connected to bones move substances through body
• Skeletal muscles – a voluntary muscle connected to bone which
allows skeletal movement
• Contracts when stimulated by motor neurons
• Movement in opposite directions requires a different muscle to control each direction
• Cardiac muscles – an involuntary muscle responsible for heart contractions
• Gap junctions allow cells to share electrical signals
• Action potential in one part of heart causes entire heart to contract
• Smooth muscles – an involuntary muscle found in organs and
blood vessels that moves substances throughout the body
• Contracts slowly over a greater length
Epithelial
• Epithelial tissue – the tissue that composes skin and lines organ surfaces
• Cells are tightly-packed
• Forms a protective covering over surfaces
• Helps exchange molecules
• Cell layers:
• Cell shapes:
• Simple epithelium – single layer of cells
• Cuboidal epithelium – cube-shaped
• Stratified epithelium – several layers of cells
• Columnar epithelium – resembles bricks
• Squamous epithelium – thin, flat appearance
• Cell layer and shape combinations produce six total types of epithelial tissue
Biology 17.2 – Specialized Tissue in Animals
Specialized Tissue in Animals
Type of Epithelium
Function
Example in the Body
Diffusion
Lining of the blood vessels
and air sacs
Protection, absorption of
nutrients, and sensory input
Digestive tract, cornea
Secretion
Kidney tubules and glands
Protection against friction
Lining of the esophagus
Secretion and protection
Lining of the urethra
Protection of ducts
Sweat glands in skin
Simple squamous
Simple columnar
Simple cuboidal
Stratified squamous
Stratified columnar
Stratified cuboidal
Biology 17.2 – Specialized Tissue in Animals