Warm-Up!!! 4/23 Cell Cycle! Label #s 1-5 and can you remember what happens in S phase of the cell...
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Transcript of Warm-Up!!! 4/23 Cell Cycle! Label #s 1-5 and can you remember what happens in S phase of the cell...
Warm-Up!!! 4/23Cell Cycle!
Label #s 1-5 and can you remember
what happens in S phase of the cell cycle?
Warm-Up!!! 4/23Cell Cycle!
1 – Prophase2 – Metaphase3 - Anaphase4 - Telophase5 - Cytokinesis
Warm-Up!!! 4/23Cell Cycle!
S Phase = DNA is
copied!!!
Warm-Up!!! 4/23Cell Cycle!
G1 = cell growth
G2 = cell prepares for division (mitosis)
Warm-Up!!! 4/23Cell Cycle!
Interphase = Any time cell
is not dividing!
Basics of the Human Body!!!
Levels of OrganizationThe levels of organization in the human
body are as follows:
CellsTissuesOrgans
Organ SystemsOrganism
Levels of OrganizationExample:
Cells -NeuronTissues -Nervous TissueOrgans -BrainOrgan Systems -Nervous SystemOrganism -Human
HomeostasisEach cell in the human body is both an independent unit and a
part of a larger community.
Each of your 100 trillion cells must work together at all times to
keep the body functioning correctly.
Homeostasis
Short definition: the body’s ability to maintain a
constant internal environment despite external changes.
Homeostasis
For example: when you go outside on a really hot day
your internal body temperature does not rise –
the body takes action to keep you at a constant 98.6
degrees.
HomeostasisThe body MUST always maintain
homeostasis or risk harm:
Homo = Same
Stasis = constant
Homeostasis
A perfect non-living example of homeostasis:
The air conditioner inyour house.
Homeostasis1. Air conditioner set at 75
degrees. 2. If the temp. warms to 76 a
sensor notes this and turns the air on.
3. When the sensor detects the temp has fallen back to 75 it shuts
the air off.4. A constant internal environment
has been kept.
HomeostasisThis kind of response is called
Negative Feedback.
That is, when a systems pushes things in the opposite direction
in response to some kind of change.
Negative Feedback!
HomeostasisThe body uses sorts of negative
feedback loops to maintain homeostasis.
Example: maintenance of a stable internal body
temperature.
HomeostasisBody’s temperature sensor is the
Hypothalmus deep inside the brain.
So, the hypothalamus is probably part of which of the 11 body
systems?
Homeostasis:1. Body temperature drops to 97
degrees.2. Nerve cells of the hypothalamus
sense the temperature change.
3. Hypothalamus releases chemicals that tell muscle cells
to ‘shiver’ to create heat.
Homeostasis:
4. Muscles produce heat that warms the body back to 98 degrees.
5. The nerve cells of the hypothalamus detects this
increase in temperature and stops releasing the chemical that tells
the muscles to shiver.
Negative Feedback!
Conclustion:Using negative feedback loops the
body can keep its internal environment within very stable limits (we call this maintaining
homeostasis).
If this process is not working properly…..you have the potential
for some serious bodily harm.