Anatomy & Physiology of the Excretory System Anatomy & Physiology 13-14.
Introduction to Anatomy and Physiology. anatomy = a cutting open o Study of internal and external...
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Transcript of Introduction to Anatomy and Physiology. anatomy = a cutting open o Study of internal and external...
Introduction to Anatomy and Physiology
anatomy = “a cutting open”o Study of internal and
external structures of the body and the physical relationship between body parts
o Ex – a particular bone attached to a muscle
physiology o Study of the function of
anatomical structures; considers both physical and chemical processes
o Ex. how a muscle contracts to move the bone
cell: basic unit of lifeo Cytologyo Histology
Levels of Organization
Homeostasis
Objectives:1. Significance of homeostasis
2. Positive and negative feedback
Start here
Lots of examples of negative feedback loops, few positive loops
For test be able to analyze:o Calcium homeostasis (page 132)o Body temperature (page 7)o Water regulation (refer to notes)o Control center for sympathetic and
parasympathetic divisions of PNSo Effectors and response after
sympathetic disruption of homeostasis occurs
Two ways to maintain homeostasis
o Negative feedbacko Positive feedback
Negative Feedback: example body temperature
Q1: compare response to original stimulus
o Answer:o The response by the effectors
is antagonistic (opposite) of the stimulus
Stimulus = body temp ↑Response = body temp ↓
Q2: homeostasis restored? How do you know?
o Answero Yes, because the response
counteracts the stimuluso Brings back balance
Positive Feedback: example labor contractions
Q3: compare response and stimulus in
positive feedback o Answer
o The response acts to heighten or increase the stimulus
Stimulus = ↑ distortion of uterus
Response= ↑ distortion and contraction of
uterus
Q4: Is homeostasis restored in this example? How do you
know?o Answer:
o No, homeostasis is continually disrupted o This is a good thing in this case b/c
returning to homeostasis would cause the birthing process to stop.
o The positive feedback loop will continue until birth is complete.
Positive feedback exampleso Childbirtho Blood clottingo Sexual orgasmo Milk production from
mammary glands
Cellular homeostasis
Every level of organization within the body must maintain homeostasis
Phospholipid Bilayer
Diffusion
o Diffusion is the movement of molecules from a higher concentration to a lower concentration.
o The difference in concentration of two solutions is called the concentration gradient
o Demonstration: food coloring in water
ttp://www.biosci.ohiou.edu/introbioslab/Bios170/diffusion/Diffusion.html
Diffusion: Anatomy exampleo Oxygen gas enter body and
blood streamo Carbon dioxide leave blood
and body
Diffusion across membranes
o Molecules that dissolve in lipids can cross the lipid bilayer through diffusion. Example: O2
CO2 H2O
Osmosis
o Think back to solutions: solutes and solvents
o Osmosis is the process by which water molecules diffuse across a cell membrane from an area of lower solute concentration to an area of higher solute concentration.
o Direction of movement depends on relative concentrations of solutions.
Osmosis: anatomy connectiono Excess water versus
dehydrationo Kidneys help to rid excess
water as urine = osmosis of water out of blood (high) into kidneys (low)
Direction of movement into cells
o Hypotonic to the cytosolo solution outside the cell is less concentrated than
inside the cell
o water moves into the cell
o Hypertonic to the cytosolo solution outside the cell is more concentrated than
inside the cello water moves out of the cell
o Isotonico concentrations are equal
ohttp://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm
What about the molecules that can’t pass through the membrane freely?
o Glucose, Na+, Ca+, K+ and lots of other molecules need to get into and out of the cell but can’t get through the lipid bilayer
o They must use the proteins embedded in the lipid bilayer
Facilitated transporto Protein channels embedded
in the cell membrane allow ions and other molecules to diffuse into and out of a cell
o Where have we seen facilitate diffusion in action?o Neuron’s gated Na+ and K+
channelso Ca+ channels in nerve and
muscle cells
Active transporto Requires energy to
transport molecules across a cell’s membrane
Ex. 1 Membrane proteins may serve as pumps to push ions across the cell against the concentration gradiento Examples of pumps?o Na+/K+ pump in neurons
Active Transport (con’t)Ex. 2 Exocyotosis – the cell
excretes wastes, chemicals or other products by releasing them from vesicleso Where have we seen this?o Release of neurotransmitters
Ex 3 Endocytosis – the cell takes in molecules or food by engulfing ito We will see this with immune
system and WBCs