Transcript Ch. 14.1 Notes

Ch. 14.1 Notes
Body Organization and Homeostasis
• The levels of organization in the
human body consist of cells, tissues,
organs, and organ systems.
• The smallest unit is the cell.
• Cell < Tissue < Organ < Organ System
Cells
• The cell is the basic unit of
structure and function in a
living thing.
• Complex organisms are
composed of many cells.
• The human body contains
about 100 trillion cells.
• Cells are so tiny, you need a
microscope to see them.
Structures of Cells
• The cell membrane forms the outside
boundary of the cell.
• The nucleus controls the cell and contains
DNA.
• The fluid a between the cell membrane and
the nucleus is the cytoplasm.
Functions of Cells
• Cells carry on the processes that keep
organisms alive.
• Cells also grow and reproduce through Mitosis
and Meiosis.
• They also get rid of waste products that result
from their activities.
Tissues
• A tissue is a group of similar cells that perform
the same function.
• The human body contains four basic types of
tissue:
• 1. muscle tissue
• 2. nervous tissue
• 3. connective tissue
• 4. epithelial tissue
Muscle Tissue
• Like the muscle cells that form it, Muscle
tissue contract, or shorten.
• This characteristic allows for your body to
move!
Nervous Tissue
• Nervous tissue directs and controls the
process of movement.
• Nervous tissue sends out electrical messages
back and forth between the brain and other
parts of the body.
• It’s like the “wiring” of your body.
Connective Tissue
• Connective tissue provides support for your
body and connects all the parts.
• It includes bones and fat cells.
Epithelial Tissue
• The surfaces of your body, inside and out, are
covered by epithelial tissue.
• Epithelial tissue = skin cells
• It also lines the digestive tissue (your stomach,
intestines, etc.)
Organs and Organ Systems
• An organ is a structure
composed of different kinds of
tissues.
– Stomach, heart, brain, lungs,
etc.
• Like tissue, an organ has a
specific job.
• However, the job of an organ
is very complex. It normally
does multiple things.
Organ Systems
• Each organ in your body is part of an organ
system, which is a group of organs that work
together to perform major function.
• We will talk about 8 organ systems:
– Circulatory
– Digestive
– Nervous
– Skeletal
-- Endocrine
-- Muscular
-- Excretory
-- Respiratory
Circulatory System
• Transports materials to and from cells.
– Heart
– Veins, arteries
– Blood cells
Digestive System
• Breaks down food and absorbs nutrients.
– Mouth, stomach, small and large intestine, colon
Nervous System
• Detects information from the environment
and controls body functions.
– Brain, spinal cord, nerves
Skeletal System
• Supports and protects the body.
– Bones, skull, ribs, etc.
Endocrine System
• Controls many body processes by means of
chemicals.
– Liver, kidney, thyroid, “glands”
Muscular System
• Enables movement of the body and internal
organs.
– Biceps, heart, stomach, thigh, calf
Excretory System
• Removes waste (poop, etc.).
– Blood cells, kidneys, bladder, colon
Respiratory System
• Takes in oxygen and eliminates carbon dioxide.
– Lungs, mouth, nose
Homeostasis
• The process by which an organism’s internal
environment is kept stable in spite of changes
in the external environment.
– “To stay the same”
– Sweat to keep cool
– Shiver to keep warm
– Drink water to stay hydrated
Stress and Homeostasis
• Sometimes, things happen to
disrupt homeostasis.
• Stress is the reaction of your
body to potentially threatening,
challenging, or disruptive events.
• Playing sports causes “stress” on
your body. To maintain
homeostasis while playing
basketball (stress), you sweat to
keep cool.