Transcript Human Body - TeacherTube

Human Body
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Levels of Organization
• The levels of organization in a multicellular
organism include cells, tissues, organs,
and organ systems.
Cells
• Cells tend to be specialized.
• Specialized cells are uniquely suited to
perform a particular function.
Tissues
• A group of cells that perform a single
function is called a tissue.
• 4 types of tissues in humans: Epithelial,
connective, nervous and muscle tissue.
Organs
• A group of different tissues that work
together to perform a single function is an
organ.
Organ System
• An organ system is a group of organs that
perform closely related functions.
• For example, the brain is one of the
organs of the nervous system.
Homeostasis
• Is the process by which organisms keep
internal conditions relatively constant
despite changes in external environments.
Feedback Inhibition
Or negative feedback, is the process in
which a stimulus produces a response that
opposes the original stimulus.
The Nervous System
The nervous system controls and
coordinates functions throughout the body
and responds to internal and external
stimuli.
Neurons
Neurons carry electrical signals called
impulses throughout the nervous system.
Cell Body
The largest part of the neuron where most of
the metabolic activity of the cell takes
place.
Dendrites
Dendrites carry impulses from the
environment or from other neurons toward
the cell body.
Axon
The axon is the long fiber that carries
impulses away from the cell body.
Myelin Sheath
• The insulating structure that surrounds the
axon.
• As an impulse moves, it is carried from
node to node.
Which structure carries impulses
away from the neuron?
A.
B.
C.
D.
Dendrite
Axon
Myelin Sheath
Cell Body
True or False: The largest structure
of a neuron is the cell body
A.
B.
C.
D.
Which structure of the neuron
carries impulses toward the
neuron?
Cell Body
Axon
Dendrite
Myelin Sheath
The Central Nervous System
• The central nervous system consists of the
brain and spinal cord.
The Brain
• The brain contains approximately 100
billion neurons.
Meninges
• Both the brain and spinal cord are
wrapped in three layers of connective
tissue known as the meninges
Cerebrospinal Fluid
• Bathes the brain and spinal cord and acts
as a shock absorber that protects the
nervous system.
The Cerebrum
• Largest part of the brain.
• Responsible for conscious activities of the
brain.
Cerebellum
• The cerebellum coordinates and balances
actions of the muscles so that the body
can move gracefully and efficiently.
Brain Stem
• The brain stem connects the brain and the
spinal cord.
• Blood pressure, heart rate, breathing and
swallowing are controlled in the brain
stem.
• It includes the pons and medullas
oblangata.
Thalamus
• The thalamus receives messages from all
of the sensory receptors throughout the
body and then relays the information to the
proper region of the cerebrum for further
processing.
Hypothalamus
• Is the control center for recognition, and
analysis of hunger, thirst, fatigue, anger
and body temperature.
Medulla
• Lower part of the brain stem
• Controls involuntary responses such as
breathing heart rate and blood pressure.
Pituitary
• Connected to the hypothalamus
• Secretes 9 hormones that maintain
homeostasis.
Spinal Cord
• The main communication link between the
brain and the rest of the body.
• 31 pairs branch out from the spinal cord to
connect the brain to the rest of the body.
Corpus Callosum
• Splits the brain into left and right
hemispheres.
Limbic System
• Controls emotion, behavior, long term
memory and olfaction.