Animal Tissues and Organ Systems
Chapter 33
AP BiologySpring 2011
Nervous Tissue
Chapter 33.4
Nervous TissueNervous Tissue: composed of neurons
and a variety of cells (called neuroglia), that structurally and functionally support them
Nervous TissueNeurons: kind of excitable cell that makes
up the communication lines in most nervous systems
Motor Neuron Neuron: highly excitable in a specific way When stimulated, propagates a message
along its plasma membrane, all the way to some outpoint zone, without altering it
Message triggers release of signaling molecules called neurotransmitters
Signals diffuse to another cell that is almost but not quite touching the neuron that sent them
NeuronsInterneurons: neurons in
your brain and spinal cord Receive and integrate
sensory information, store the bits that hold meaning, and coordinate the body’s short-term and long-term responses to stimuli
Motor Neurons: relay commands from brain and spinal cord to muscle cells
Overview of Major Organ Systems
Chapter 33.5
Organ SystemsGerm cells give rise to sperm or eggFertilization zygote forms Mitotic cell divisions three primary tissue
layers Forerunners of all adult tissues and organs
Three Primary Tissue LayersEctoderm: the outer
layer, is the first to form Gives rise to epidermis and
the nervous system Mesoderm: middle layer,
start of muscles, bones, and most of circulatory , urinary, and reproductive systems
Endoderm: inner primary tissue layer, start of lining of digestible tract and organs derived from it
Division of LabourDivision of Labor: organ systems of
multicelled body show this compartmentalization of function Help body survive in ways no one tissue can
offer
Division of Labor Organ systems divide up tasks of securing,
processing, and distributing materials, and expelling wastes, protecting the body, integrating its activities, and reproducing
Organ SystemsIntegumentary
SystemsProtects body from
injury, dehydration, and some pathogens; controls its temperature; excretes certain wastes, receives some external stimuli
Organ SystemsNervous System:
Detects external and internal stimuli; controls and coordinates the response to stimuli; integrates all organ system activities
Organ SystemsMuscular
System: Moves body and
its internal parts; maintains posture; generates heat and increases metabolic activity
Organ SystemsSkeletal System:
Supports and protects body parts; provides muscle attachment sites; produces red blood cells; stores calcium, phosphorous
Organ SystemsCirculatory
System:Rapidly transports
many materials to and from cells; helps stabilize internal pH and temperature
Organ SystemsEndocrine System:
Hormonally controls body functioning; works with nervous system to integrate short-term and long-term activities
Organ SystemsLymphatic
System:Collects and returns
some tissue fluid to the bloodstream; defends the body against infection and tissue damage
Organ SystemsRespiratory System:
Rapidly delivers oxygen to the tissue fluid that bathes all living cells; removes carbon dioxide wastes of cells; helps regulate pH
Organ SystemsDigestive System:
Ingests food and water; mechanically, chemically breaks down food and absorbs small molecules into internal environment; eliminates food residues
Organ SystemsUrinary System:
Maintains the volume and composition of internal environment; excretes excess fluid and blood borne wastes
Organ SystemsReproductive System:
Female: produces eggs; after fertilization affords a protected, nutritive environment for the development of a new individual
Male: produces and transfers sperm to the female; hormones of both systems also influence other organ systems
CavitiesCranial cavity Spinal cavity Thoracic cavity Abdominal cavity Pelvic cavity
Directional Terms and Planes Direction: dorsal, ventral, posterior,
anterior
Directional Terms and Planes Planes: frontal, midsagittal , transverse
Directional Terms and Planes Anterior: at or near front of body Posterior: at or near back of body Superior: of two body parts, the one
closest to the head Inferior: of two body parts the one
farthest from the head Proximal: closest to trunk or point of
origin of a body part Distal: farthest from trunk or from point
of origin of a body part
Vertebrate Skin: An Example of an Organ System
Chapter 33.6
SkinOuter body covering has the largest
surface area Two layers: underlying dermis and outer
epidermis
DermisDense connective tissue with many fibers
of stretch resistant elastin and supportive collagen
Blood vessels, lymph vessels, sensory receptors thread through it
Rest on hypodermis: not part of skin, contains loose connective tissue and adipose tissue
DermisDermis contains exocrine glands
Sweat glands Oil glands (except on palms and soles)
EpidermisStratified squamous epithelium with an
abundance of adhering junctions and no extracellular matrix
Ongoing mitotic cell divisions in the deepest layers push previously formed cells to the surface
EpidermisWear and tear from surface and pressure
from growing mass, flatten and kill cells before they reach the surfaceDead one are flaked off
Main types: keratinocytes, melanocytes, dendrite cells
EpidermisKeratinocytes: sectret keratin, tough,
water resistant protein, makes skin water proof and more durable Dead, flattened keratinocytes make up hair
EpidermisMelanocytes: produce brownish-black
pigment melanin (gives up pigments to keratinocytes) Body’s barrier to UV radiation
Variations in skin colour result from differences in the distribution and activity of melanocytes
EpidermisLangerhans: migrate through epidermis
Engulf bacteria or viruses, communicate with immune system
UV radiation damages these cells and skin will be more vulnerable to viral outbreaks
EpidermisLab-grown epidermis: used to protect
tissues and aid wound healing in some patients
A new tattoo removal procedure developed by the Wake Forest Institute in North Carolina for Regenerative Skin Treatment was recently used by rapper Pharrell Williams. The procedure involves the patient providing a sample of his/her skin from which is grown in a laboratory enough new skin to cover the tattooed area. Supposedly the new skin is stitched over the tattoo and does not leave any scars. Once the skin has healed, new tattoos can be done.
Suntans and Shoe-LeatherUV light stimulates melanocytes in skin to
make melanin and gives skin “tan” look Chronic UV damage causes skin to be less
resilient and starts to look like shoe leather UV attacks DNA causing skin cancer
Suntans and Shoe-LeatherAs we age, epidermal cells divide less often Skin thins, becomes less elastic as collagen
and elastin fibers become sparse Glandular secretions dwindle, wrinkles
deepen
Vitamin ConnectionUV stimulates vitamin D production
Helps body absorb calcium UV aids breakdown of folate (B vitamin) Variations in skin colour may be
adaptations to differences in sunlight xposure