Homeo Flashcards
What is essential for homeostasis in the body?
Communication within the body is essential for homeostasis
Which systems are chiefly responsible for communication in the body?
The nervous and endocrine systems
What are the information carriers used by the nervous and endocrine systems?
Neural electrical impulses and blood-borne hormones
What is the variable in a homeostatic control mechanism?
The factor or event being regulated
How many components are involved in all homeostatic control mechanisms?
At least three components
What is the role of the receptor in homeostasis?
It is a sensor that monitors the environment and responds to stimuli
What does the receptor send information along to?
The afferent pathway to the control center
What is the function of the control center in homeostasis?
It determines the set point and analyzes input to determine the appropriate response
What is a set point in the context of homeostasis?
The level (or range of levels) at which a variable is to be maintained
What type of information flows from the control center to the effector?
Output information
What is the effector’s role in the homeostatic process?
It carries out the control center’s response to the stimulus
Fill in the blank: Information traveling along the _______ pathway approaches the control center.
afferent
Fill in the blank: Information exits from the control center along the _______ pathway.
efferent
What happens to the stimulus as a result of the effector’s response?
It can be reduced or enhanced
True or False: The effector’s response can only reduce the stimulus.
False
What influences the effect of the stimulus in homeostasis?
The results of the response from the effector
What does the fluid mosaic model of membrane structure depict?
The plasma membrane as a thin structure composed of a lipid bilayer with proteins dispersed in it
The model is characterized by a constantly changing mosaic pattern formed by proteins.
What is the thickness range of the plasma membrane?
7-10 nm
This measurement indicates the exceedingly thin nature of the plasma membrane.
What primarily composes the lipid bilayer of the plasma membrane?
Phospholipids, with smaller amounts of cholesterol
The lipid bilayer forms the basic ‘fabric’ of the membrane.
What is the orientation of the hydrophilic heads of phospholipids in the membrane?
They lie on both the inner and outer surfaces of the membrane
This orientation is due to their attraction to water.
What do the nonpolar tails of phospholipids do in the membrane?
They line up in the center of the membrane, avoiding water
This creates a sandwich-like structure in biological membranes.
What is the general structure of all biological membranes?
Two parallel sheets of phospholipid molecules lying tail to tail
The polar heads are bathed in water on either side.
What property of phospholipids encourages biological membranes to self-assemble?
Their self-orienting property
This property helps membranes to reseal themselves when torn.
How does the plasma membrane’s consistency compare to everyday substances?
It is similar to olive oil
This indicates the dynamic fluid nature of the plasma membrane.
How do phospholipids move within the plasma membrane?
They move freely from side to side, parallel to the membrane surface
They rarely flip-flop or move between the bilayer halves.
What percentage of membrane lipid is cholesterol?
20%
Cholesterol plays a role in stiffening the membrane.
What are the two distinct populations of proteins found in the plasma membrane?
Integral and peripheral proteins
Integral proteins are embedded in the membrane, while peripheral proteins are attached to the surface.
What role do proteins play in the plasma membrane?
They allow the cell to communicate with its environment
Proteins are responsible for most specialized membrane functions.
True or False: Proteins make up about half of the plasma membrane by mass.
True
This highlights the significant role of proteins in membrane structure.
Fill in the blank: The polar heads of phospholipids are attracted to _______.
water
This attraction is due to the hydrophilic nature of the heads.
What happens to the inward-facing and outward-facing surfaces of the plasma membrane?
They differ in the kinds and amounts of lipids they contain
These variations help determine local membrane structure and function.
