Physio lab sir bautista:)))

1. General
Physiology

2. The study of the properties which
are common to all cells and living
beings (claude bernard).
Among these common properties,

there are the major metabolic
pathway already studied during
the general biochemistry lectures.

3. Learning outcomes of the course :
•To be able to explain how the cell structure is maintained meanwhile this
cell assume a particular function (cell membrane permeability, cellular
volume regulation, muscle contraction, transmission of nervous information
•To be able to give a molecular explanation to the phenomenon
characterizing the living organisms.
•To be able to give a global explanation about the complexity of the
coordination system regulating the interactions between the various
systems of the organism.
•To be able to describe the relationships between specific metabolic
pathways and the environmental properties.
•To be able to use all these informations to start in good conditions the
study of Human Physiology.

4. Recommended or required readings :
Guyton
Marieb
Ganong
Supplemental laboratory modules (Dr. Bautista)

5. REQUIREMENTS:
-Laboratory exercises
-Journal Research Work
-Laboratory exams/quizzes
-Group Presentation

6. •Students will sign up for a group and topic on the first day of class.
The presentation topic should be a disease related to the physiological
system covered in class that day.
The entire presentation should be limited to 10 minutes; and include the
following sections:
ackground: introduced the disease, how many are affected, who is
affected, symptoms, complication, history of the disease, when discovered,
etc.
Diagnostic procedure: discuss how the disease is diagnosed.
Mechanism: what is the causative agent? Bacteria, virus, fungus,
autoimmune, hereditary, other? How does the disease result from the
causative agent?
Treatment: how is the disease treated? Drugs, surgery, alternative
therapy, lifestyle modifications, etc.
Current research: recent clinical trials and/or innovations on the
topic.
Appropriate citations must be included on the last slide. The cited
sources must be credible, scientific, and peer reviewed journals, or other
publication. References may be subject to verification at the discretion of your
lab instructor. Wikipedia is not allowed

7. Lab 1
HOMEOSTASIS & DIFFUSION

8. What is Homeostasis?
• A dynamic constancy of the internal physiological
environment.
– the control of a vital parameter
• Maintained by feedback control mechanisms.
• The inability to maintain homeostasis indicates
disease.
Physiology: the study of biological functions and
processes of the human body under normal conditions.
– Function explains “why”
– Process describes “how”

9. Feedback Control Systems
• Feedback is the flow of information along a closed
loop.
• A single feedback loop does not operate in isolation,
but rather as part of a large network of controls.
Must be to perform the following functions:
– The system must be able to sense the vital parameter.
– The system must be able to respond to changes in the
vital parameter by producing some sort of signal.
– The signal must act in such a way as to produce an effect
that controls the vital parameter.

10. Components of Control Systems
Input Output
information sent along afferent information sent along efferent
pathway to control center pathway to effector
Control
Center
Receptor Effector
Response
Fed back to influence
the effect of stimulus,
either reduces it
(negative) so controlled
Stimulus variable returns back to
Causes a change in BALANCE normal, or enhances it
Controlled variable (positive) so the whole
process continues at a
faster rate.
Copyright © Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

11. Negative Feedback Mechanism
• Action taken by the effectors to oppose
changes in the controlled variable caused by a
stimulus.
– (e.g., thermostat regulation of room temperature)
– Supports homeostasis
– Most common feedback mechanism in nature.

12. Figure 1.5 - Regulation of body temperature by a negative feedback mechanism.
Control Center
thermoregulatory
center in brain
Receptors
Temperature-sensitive Effectors
cells in skin and brain Sweat glands
Sweat glands activated
Response
Evaporation of sweat
Stimulus Body temperature falls
Body temperature
BALANCE
rises
Stimulus
Response
Contractions generate heat Body temperature falls
Body temperature rises
Receptors
Effectors
Temperature-sensitive
Skeletal muscles
cells in skin and brain
Shivering
begins
Control Center
thermoregulatory
center in brain
Copyright © Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

13. Positive Feedback Mechanism
• Actions taken by effector amplify the changes caused by
the initial stimulus; therefore, resulting in further deviation
from homeostasis.
– (e.g., blood clotting, child birth, etc.)
• Does not support homeostasis
• Less common in nature

14. Part II:
MEMBRANE TRANSPORT

15. Structure Of Plasma Membrane
Copyright © The McGraw-Hill Companies, Inc. All Rights Reserved.

16. Selective Permeability
• The plasma membrane is selectively
permeable; allowing certain molecules
to “penetrate” or “permeate” the
membrane, while excluding others.
– Hydrophobic, nonpolar molecules readily
diffuse across the lipid bilayer membrane
without the aid of membrane proteins.
– Some very small, uncharged polar
molecules, like water, are able to squeeze
between tiny spaces created by the
phospholipid tails as they sway in the fluid
environment.

17. Membrane Transport
Passive Transport – movement of a substance down its
concentration gradient; does not require energy.
Active Transport – movement of a substance against its
concentration gradient; requires energy (ATP).

18. Passive Transport

19. Simple Diffusion
(diffusere means “to spread out”)
• Passive transport across plasma membrane without assistance from a
transporter protein.
• The tendency for molecules within a particular space to become even
distributed over time.
• Molecules move down their own concentration gradient; from a region
of [High] concentration  [Low] concentration.
• Continues until a dynamic equilibrium is reached.

20. Channel-mediated facilitated diffusion
• Specialized channel proteins create hydrophilic tunnels in the lipid
bilayer; thus facilitating the transport of small, polar molecules and ions
across the membrane at much faster rates than in carrier-mediated
transport.
• Transport of solute passively down its concentration gradient; from
[High]  [Low] concentration.
• Channel proteins are highly selective; allowing only specific molecules or
ions of a certain size to cross the membrane
• May be either entirely open or closed on both sides of the plasma
membrane. Na+

21. Carrier-mediated facilitated diffusion
• Specialized proteins that facilitate the transport of larger,
hydrophilic (polar) molecules across the plasma membrane;
generally too large to fit through channels.
• Carrier proteins bind to the solute to be transported and move it
through the membrane by undergoing a conformational change; this
slows the transport of solute
• Carriers are highly selectively
• [High]  [Low] concentration

22. Primary Active Transport
• Carrier protein uses energy to
move a substance against its
concentration gradient.
– Molecules are “pumped”
against a concentration
gradient at the expense of
energy.
– [Low]  [High] concentration
– Establishment of concentration
gradient is a consequence of
transport.
– Direct use of energy (ATP)

23. Secondary Active Transport
• Transport is driven by the energy stored in the concentration gradient of another
molecule (Na+)
– downhill movement of one molecule drive uphill movement of another molecule.
– Utilizes established concentration of molecule A to power transport of molecule B
– indirect use of energy (ATP)
• Categories of Transport:
– Cotransport (symport): driver ion and molecule move in same direction across plasma
membrane.
– Countertransport (antiport): driver ion and molecule move in opposite directions across
plasma membrane.

24. Osmosis
• The simple diffusion of water across a selectively
permeable membrane; that allows water molecules to
freely permeate the membrane but obstructs larger solute
molecules.
• Water moves down its own concentration gradient

25. Tonicity of Solutions
• Isotonic solutions – both solutions have the
same concentration of solutes.
– No net movement of water
• Hypotonic solution – lower concentration of
solutes
– Cells will lyse
• Hypertonic solution – higher concentration
of solutes.
– Cells will crenate

26. Normal cell volume
Intracellular fluid: 300 mOsm
nonpenetrating solutes
H2O H2O
300 mOsm 200 mOsm 400 mOsm
nonpenetrating solutes nonpenetrating solutes nonpenetrating solutes
No net movement of H2O; Water diffuses into Water diffuses out of
no change in cell volume. cells; cells swell (lyse). cells; cells shrink (crenate).
(a) Isotonic (b) Hypotonic (c) Hypertonic
conditions conditions conditions Copyright © 2010 Cengage Learning

27. Next meeting:
• Laboratory exercises on Homeostasis and
Transport Mechanisms.