animal tissues and organ systems chapter 33 ap biology spring 2011

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