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Lesson Overview
30.1 Organization of
the Human Body
Lesson Overview
Organization of the Human Body
Question #1
Levels of Organization (smallest to largest)
Cells = Basic unit of structure and function in living things
Our specialized cells are uniquely suited to perform a particular
function
Tissues = A group of cells that perform a single function
Types include epithelial, connective, nervous, and muscle
Organs = A group of different tissues that work together to perform a
single function or several related functions
Organ Systems = A group of organs that perform closely related
functions (interact to maintain homeostasis in the body as a whole)
Lesson Overview
Organization of the Human Body
Question #2
Types of Tissues
Epithelial Tissue
Functions = Protection, absorption, excretion of
materials
Locations = Skin, lining of digestive system, certain
glands
Lesson Overview
Organization of the Human Body
Question #2
Types of Tissues
Connective Tissue
Functions = Binding of epithelial tissue to structures,
support, transport of substances
Locations = Under skin, surrounding organs, blood,
bones
Lesson Overview
Organization of the Human Body
Question #2
Types of Tissues
Nervous Tissue
Functions = Receiving and transmitting nerve impulses
Locations = Brain, spinal cord, nerves
Lesson Overview
Organization of the Human Body
Question #2
Types of Tissues
Muscle Tissue
Functions = Voluntary and involuntary movements
Locations = Skeletal muscle, muscles surrounding
digestive tract and blood vessels, heart
Lesson Overview
Organization of the Human Body
Question #3
Human Body Systems
Lesson Overview
Organization of the Human Body
Question #3
Human Body Systems
Lesson Overview
Organization of the Human Body
Question #4
Homeostasis
“Similar standing”
The relatively constant internal physical and chemical
conditions that organisms maintain despite changes in
internal and external environments
The systems of the body work to keep internal conditions within a
certain range, never allowing them to go too far one way or the other
This is like keeping a car in the center of a lane – you constantly move
the steering wheel to the left and the right
Lesson Overview
Organization of the Human Body
Question #5
What is feedback inhibition?
Negative feedback
The process in which a stimulus produces a response that
opposes the original stimulus
Lesson Overview
Organization of the Human Body
Question #6
Feedback inhibition = Home heating system
When the furnace is switched on, it produces heat
This raises the air temperature in the house
This environmental change then “feeds back” to “inhibit” the
operation of the furnace
The furnace is switched off
Lesson Overview
Organization of the Human Body
Question #7A
Feedback inhibition = Maintaining body temperature
If the body temperature begins to cool, the hypothalamus in
the brain signals the body cells to speed up activities, such
as cellular respiration, which creates heat (sometimes your
body will begin to shiver to produce heat)
Also, a message is sent to the skin capillaries to constrict
(which means less heat is lost as radiation)
Also, a message is sent to the sweat glands to stop
perspiration (less heat is lost by evaporation)
Lesson Overview
Organization of the Human Body
Question #7B
Feedback inhibition = Maintaining body temperature
If the body temperature rises, the hypothalamus in the brain
signals the body cells to slow down activities, producing
less heat
Also, a message is sent to the skin capillaries to dilate (which
means more heat will be lost as radiation)
Also, a message is sent to the sweat glands to produce sweat
and perspiration begins (heat will be lost by evaporation)
Lesson Overview
Organization of the Human Body
Question #8A
The liver and homeostasis
The liver converts ammonia (which is a toxic byproduct
produced when proteins are broken down for energy) to
urea, which is much less toxic
The kidneys then remove urea from the blood
The liver also converts other substances (drugs, etc.) into
compounds that can be removed from the body safely
Lesson Overview
Organization of the Human Body
Question #8B
The liver and homeostasis
Also, the liver helps to regulate the level of glucose…
When glucose levels are high the liver converts the glucose
into glycogen and stores it
When glucose levels are low the liver breaks down the
glycogen and releases glucose
This is important because too little glucose can result in cells
slowing down and too much glucose can damage cells of
the eyes, kidneys, heart, and the immune system