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The study of human parts visible to the eye
The study of Cells (cytology) and Tissues (histology)
The science that deals with the functions of the living organism and it's parts.
How many 'Levels of Organization'? And What are they?
- 1. Chemical Level - Basis of Life
- 2. Organelle Levels
- 3. Cellular Level
- 4. Tissue Level
- 5. Organ Level
- 6. Organ System Level
- 7. Organism Level
Describe the 'Chemical Level'.
This level deals with atoms and their formation/bonding into Molecules (Chemical groupings). The unique and complex relationships which exists between atoms, molecules, and macromolecules.
Describe the 'Organelle Level'.
Chemical structures may be organized within larger units termed "Cells", to form various structures called "Organelles".
Organelles are a structure made up of molecules to perform a specific function. Organelles are tiny organs which allow cells to live. Organelles cannot live outside the Cell, and without Organelles, Cells can't live.
Describe the 'Cellular Level'.
The Chemical Level and Organelle Level serve as building blocks for the next level of body structure, the "Cellular Level".
Cells are the smallest and most numerous structural units that possess and exhibit the basic characteristics of living matter.
Each Cell is surrounded by a membrane and is characterized by a single nucleus surrounded by cytoplasm (includes numerous organelles required for the normal processes of living. Different cells have different functions e.g. Fat Cells store fat.
Describe the 'Tissue Level'
Beyond the Cellular level, represents progressive organisation of living matter. A tissue is a group of a great many similar cells that all developed together from the same part of the embryo and all perform a certain function. There are four main Tissue types: epithelial, connective, muscle, and nervous. Tissues are the "Fabric" of the body.
Describe the 'Organ Level'.
More complex than the tissue level, an organ is a structure made up of several different kinds of tissues arranged so that, together, they can perform a special function. If tissues are the fabric of the body, an organ is like an item of clothing with a specific function made up of different fabrics.
The Heart is an example of the Organ Level. muscle and connective tissues give it shape and pump blood; epithelial tissues line the cavities, and nervous tissues permit control of the pumping contractions of the heart.
Tissues seldom exist alone, they join together to form organs. Each organ has a unique shape, size, appearance, and placement in the body, and each can be identified by the pattern of tissues that form it. E.g. are Lungs, heart, brain, kidneys, liver, and spleen.
Describe the 'System Level'.
System are the most complex of the organizational units of the body. The system level involves varying numbers and kinds of organs arranged so that, together, they can perform complex functions for the body.
There are 11 major systems in the body. See p. 9 Table 1-2.
Describe the 'Organism Level'.
The total Human Body, able to reproduce, maintain, and repair parts. Maintain a 'normal' body temperature, blood levels, elimination of waste etc.
What are the four 'Principal Types of Tissues'?
1. Epithelial tissue (e-pa-fe-le-all) - covers and protects the body surface, lines body cavities, specializes in moving substances into and out of the body or particular organs (secretion, excretion, and absorption), forms many glands. Epithelial tissues are closely together with very little extracellular matrix. E.g. Outer Layer of skin, Glands of the body, Lining of the respiratory, digestive, urinary, reproductive tracts. p. 135
2. Connective Tissue - supports the body and it's parts, connects and holds them together, transport substances through the body, and protect it from foreign invaders. Cells in connective tissue often far apart and separated by large quantities of matrix. E.g. Bones, Joint cartilage, Tendons and ligaments, Blood, Fat.
3. Muscle tissue - produces movement, moves the body and it's parts. Muscle cells contract to make movement. Muscle tissue produces most of the heat of the body. E.g. Heart Muscle, Muscles all over the body.
4. Nervous tissue - may be most complex tissue in the body. Specializes in communication between various parts of the body and in integration of their activities. Major function is the generation of complex messages that coordinate the body functions. E.g. Tissue of the brain and spinal cord, nerves of the body, sensory organs of the body.
What is Homeostasis?
The maintenance of relatively constant internal conditions despite changes in either the internal or the external environment that characterises homeostasis.
In the movement of substances through cell membranes, what is Passive Transport Processes?
1. Diffusion/Simple Diffusion - when molecules pass directly through the membrane.
2. Osmosis - the diffusion of water through a selectively permeable membrane.
3. Channel-Mediated Passive Transport (Facilitated diffusion) - Diffusion of particles through a membrane by means of channel structures in the membrane (particles move down their concentration gradient). Gated Channels, are selectively permeable.
4. Carrier-mediated passive transport (facilitated diffusion) - Diffusion of particles through a membrane by means of carrier structures in the membrane (particles move down their concentration gradient). Carrier attracts a solute to a binding site, changes its shape, and then releases the solute to the other side of the membrane.
Amoeba. They depend on the immediate external environment to provide conditions conducive to their survival.
- cells specialize and then combine to form tissues, organs and organ systems which are capable of providing individual cells with a stable environment INSIDE the body.
- - External environment is less critical for survival.
- - However, the Internal Environment (Extracellular Fluid, ECF) which surrounds individual cells must be maintained within acceptable limits.
type of membrane channels, these channels permit water molecules to diffuse through a cell membrane much more rapidly than by simple diffusion.
Is a natural phenomenon caused by the tendency of small particles to spread out evenly within any given space.
During diffusion, molecules move from an area of high concentration to an area of low concentration i.e. molecules tend to move from the side of the membrane with high concentration to the side of the membrane with a lower concentration of that molecule (the movement is known as moving down the concentration gradient).
Permeate (or Permeant) vs Impermeant
When molecules are allowed to cross a membrane, Permeate or Permeant.
When molecules can't cross - Impermeant.
A special case of diffusion. Osmosis is the diffusion of water through a selectively permeable membrane. Osmosis is accomplished through small water channels called 'aquaporins'.
Note: adding volume to a cell by water increases its pressure e.g. water balloon (the cell) being filled with water. Water pressure which develops due to osmosis is called osmotic pressure.
A fluid (solution) that has the same potential osmotic pressure as a cell. Therefore, no increase in pressure to the Cell.
The solution/fluid has a higher concentration of impermeant solutes than that found in the cell, therefore, has a higher potential osmotic pressure. The extracellular solution is said to be hypertonic (high pressure) to the intracellular solution (cytosol).
Cells placed in hypertonic solutions always shrivel.
Low pressure, because of low concentration of impermeant solutes thus a higher water concentration, than the opposite solution.
(SY-toe-sol)The fluid and semifluid matrix of the cytoplasm in which the organelles of the cell are suspended.
Extracellular fluid (ECF) and Intracellular fluid (ICF)
Extracellular fluid - the portion of body fluid located outside cells, this includes plasma (fluid inside the vessels or veins but outside of blood cells circulating the vessels) and interstitial fluid (fluid outside of the veins and outside of Tissue cells).
Intracellular fluid (ICF) are the fluids inside the cells.
(oz-mo-LAR-ih-tee)The osmotic pressure of a solution, measured in osmoles or milliosmoles perlitre.
There are three classifications of tonicity that one solution can have relative to another. The three are hypertonic, hypotonic, and isotonic.
Tonicity is a measure of the osmotic pressure gradient (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane.
It is commonly used when describing the response of cells immersed in an external solution. Like osmotic pressure, tonicity is influenced only by solutes that cannot cross the membrane, as only these exert an osmotic pressure. Solutes able to freely cross the membrane do not affect tonicity because they will always be in equal concentrations on both sides of the membrane.
What is 'Resting Membrane Potentials (RMP)'?
When a neuron is not conducting electrical signals, it is said to be 'resting'. RMP refers to the fact that the inside of the cell membrane is negatively charged compared to its external, at rest a neuron's membrane potential is maintained at about -70mV. surface (if the outside of the membrane is at 0mV).
What is the major determinant of RMP and why?
K+ is the major determinant of RMP, because the cell membrane is normally more permeable to K+.
What are the Homeostatic Control Mechanisms?
- 1. Sensor mechanism
- 2. Integrating, or control, center
- 3. Effector mechanism
- 4. Feedback
What's the importance of Homeostatic Control Mechanisms?
Maintenance of Homeostasis means that the cells of the body are in an environment that meets their needs and permits them to function normally under changing external conditions.
What is afferent and efferent?
Locational terms, used to describe movement of a signal from a sensor mechanism to a particular integrating or control centre and, in turn, movement of a signal from that center to some type of effector mechanism.
afferent - describes the signal traveling toward a particular center or point of reference.
efferent - describes the signal moving away from the center or other point of reference.
What is Controlled Variable? Set Point? Reference Point? and Variation?
Controlled variable - The variable that the system tries to keep stable e.g. the speed of a car on a motorway
Set Point - for a controlled variable, target value for controlled variable, e.g. speed limit.
Reference (normal) range - for controlled variable, values of the controlled variable within acceptable limits. e.g. what speed most 'normal' people are driving between.
Variation - in controlled variable values within and between normal people (inter and intra individual variation). Genetic factors determine different set points in different individuals (Inter-Individual variation). Variation may also occur within an individual (intra-individual variation).
Negative Feedback Control System
Negative feedback systems oppose the change in the controlled variable and move it back toward the 'set point'.
- Key components:
- 1. Sensor
- - monitors the actual value of the controlled variable.
- 2. Integrator
- - compares actual and set point values
- - determines and controls the response
- (Sensor and Integrator can be the same CELL)
- 3. Effector(s)
- - produce the response(s) that restore the controlled variable to its 'set point'.
- 4. Communication pathways
- - carry signals between components