Unit OneUnit One

““From Cells to Organ From Cells to Organ Systems”Systems”

Levels of OrganizationLevels of Organization All living things have a level of organization All living things have a level of organization

based on their specific compositionbased on their specific composition A Prokaryotic organism is made of just one A Prokaryotic organism is made of just one

cellcell A Eukaryotic organism is made of millions A Eukaryotic organism is made of millions

to trillions of cells depending on the species to trillions of cells depending on the species to which the individual belongsto which the individual belongs

Humans are, of course, Eukaryotic; a person Humans are, of course, Eukaryotic; a person is composed of trillions of cells functioning is composed of trillions of cells functioning in concert to enable the individual to livein concert to enable the individual to live

Levels of OrganizationLevels of Organization

Within a person, or any eukaryotic Within a person, or any eukaryotic organism, there is a level of organism, there is a level of organization of structures which is as organization of structures which is as follows:follows:

Atoms - - > Molecules/Compounds - - > Atoms - - > Molecules/Compounds - - > Organelles - - > Cells - - > Tissue - - > Organelles - - > Cells - - > Tissue - - > Organs - - > Organ Systems - - > Organs - - > Organ Systems - - > OrganismOrganism

Epithelial TissueEpithelial Tissue

Epithelial Tissue consist of layers of Epithelial Tissue consist of layers of cells that cover and protect various cells that cover and protect various surfaces and body cavitiessurfaces and body cavities

Glands are specialized Epithelial Glands are specialized Epithelial Tissues because they synthesize and Tissues because they synthesize and secrete a fluidsecrete a fluid Exocrine Glands – secrete fluid to the Exocrine Glands – secrete fluid to the

outside of the individualoutside of the individual Endocrine Glands – secrete a specific fluid Endocrine Glands – secrete a specific fluid

known as a Hormone into the blood stream known as a Hormone into the blood stream within the bodywithin the body

Epithelial TissueEpithelial Tissue

Epithelial Tissues are classified by Epithelial Tissues are classified by shape and number of cell layersshape and number of cell layers Simple Epithelium are composed of a Simple Epithelium are composed of a

single layer of cellssingle layer of cells Stratified Epithelium are composed of Stratified Epithelium are composed of

multiple layers of cells aka “Strata”multiple layers of cells aka “Strata”

Categories of Epithelial Categories of Epithelial TissueTissue

Connective TissueConnective Tissue

Supports the softer organs of the Supports the softer organs of the body against gravity and connects body against gravity and connects parts of the body to each otherparts of the body to each other

Collagen Fibers – made of protein, Collagen Fibers – made of protein, add strength/integrity to organs and add strength/integrity to organs and are slightly flexibleare slightly flexible

Cartilage – is the transition tissue Cartilage – is the transition tissue from which bone develops; maintains from which bone develops; maintains the shape of certain body parts (nose) the shape of certain body parts (nose) and protects/cushions joints and protects/cushions joints

Connective TissueConnective Tissue

Bone – specialized connective tissue Bone – specialized connective tissue that contains only a few living cells; that contains only a few living cells; most of bone structure consists of hard most of bone structure consists of hard mineral deposits of calcium and mineral deposits of calcium and phosphatephosphate

Blood – consists of cells suspended in a Blood – consists of cells suspended in a fluid matrix called “Plasma”; considered fluid matrix called “Plasma”; considered connective tissue because all blood cells connective tissue because all blood cells are derived from earlier cells located are derived from earlier cells located within bonewithin bone

Connective TissueConnective Tissue

Adipose Tissue – highly specialized Adipose Tissue – highly specialized for fat storage; located primarily for fat storage; located primarily under the skin where it serves as a under the skin where it serves as a layer of insulation and also forms a layer of insulation and also forms a protective layer around internal protective layer around internal organsorgans

Muscle TissuesMuscle Tissues

Consist of specialized cells that are able to Consist of specialized cells that are able to shorten and contract, resulting in movementshorten and contract, resulting in movement

Skeletal Muscle Tissue – connects to Skeletal Muscle Tissue – connects to tendons, which attach to bones; it is tendons, which attach to bones; it is voluntary muscle because we can exert voluntary muscle because we can exert conscious control over itconscious control over it

Cardiac Muscle Tissue – found only in the Cardiac Muscle Tissue – found only in the heart; individual cells are much shorter than heart; individual cells are much shorter than Skeletal Muscle cells and this tissue is Skeletal Muscle cells and this tissue is considered involuntary because the heart considered involuntary because the heart beats on its ownbeats on its own

Muscle TissueMuscle Tissue

Smooth Muscle Tissue – surrounds Smooth Muscle Tissue – surrounds hollow organs and tubes (blood hollow organs and tubes (blood vessels, digestive tract, uterus, vessels, digestive tract, uterus, bladder); these cells are much bladder); these cells are much smaller than Skeletal Muscle cells smaller than Skeletal Muscle cells and it is involuntary like Cardiac and it is involuntary like Cardiac Muscle Muscle

Nervous TissueNervous Tissue Consists primarily of cells that are Consists primarily of cells that are

specialized for generating and specialized for generating and transmitting electrical impulses transmitting electrical impulses throughout the bodythroughout the body

Neurons are those specialized cells that Neurons are those specialized cells that transmit electrical impulsestransmit electrical impulses

Glial Cells are found in Nervous tissue Glial Cells are found in Nervous tissue but do not transmit electrical impulses; but do not transmit electrical impulses; their role is to surround and protect their role is to surround and protect neurons and also supply them with neurons and also supply them with nutrientsnutrients

Organs & Organ SystemsOrgans & Organ Systems

Organ – structure composed of two or Organ – structure composed of two or more tissue types that perform a specific more tissue types that perform a specific function or multiple functionsfunction or multiple functions

Organ System – a group of organs that Organ System – a group of organs that serve a broader function that is vital to serve a broader function that is vital to the organism/speciesthe organism/species

Body Position/DirectionBody Position/Direction

The Skin The Skin The Skin aka Integumentary System has The Skin aka Integumentary System has

many functions: protect from dehydration, many functions: protect from dehydration, defense against microorganismal infection, defense against microorganismal infection, regulation of body temperature, and aids in regulation of body temperature, and aids in some sensory perception (touch, vibration, some sensory perception (touch, vibration, pain etc.) pain etc.)

Skin consists of the Epidermis (outer layer Skin consists of the Epidermis (outer layer of cells) and the Dermis (inner layer of of cells) and the Dermis (inner layer of connective tissue)connective tissue)

Melanocytes – located near the base of the Melanocytes – located near the base of the epidermis and produce a dark brown epidermis and produce a dark brown pigment known as Melanin (protects pigment known as Melanin (protects against UV Rays)against UV Rays)

The SkinThe Skin

Eukaryotic Species & Eukaryotic Species & HomeostasisHomeostasis

Humans, who are Eukaryotic, must Humans, who are Eukaryotic, must keep their bodies in a state of dynamic keep their bodies in a state of dynamic equilibrium where fluid amounts are equilibrium where fluid amounts are always in flux but do not fluctuate always in flux but do not fluctuate greatlygreatly

Maintaining the body’s dynamic Maintaining the body’s dynamic equilibrium is known as “Homeostasis”equilibrium is known as “Homeostasis” Water levelsWater levels - Nutrient levels - Nutrient levels Internal Temperature - Hormone levels Internal Temperature - Hormone levels