A&P Chapter 3
The state of solute equilibrium because
the cell membrane is freely permeable to water.
Osmosis
the diffusion of water across a membrane.
Water molecules tend to flow across a membrane toward the solution that contains _____________. p. 66
the higher solute concentration.
Diffusion
the net movement of molecules from an area of relatively high concentration (of many collisions) to an area of relatively low concentration (of fewer collisions). -often described as proceeding "down a concentration gradient" or "downhill".
Membrane Transport: permeability
the property that determines precisely with substances can enter or leave the cytoplasm.
Cytology
the study of the structure of the cell.
hydrophobic
water fearing. insoluble in water. tails on the inside.
hydrophilic
water loving. soluble in water. heads are on the outside.
Extracellular fluid
watery medium surrounding the cell
Membrane Transport: impermeable
when nothing can cross the membrane.
Solutions of various solute concentrations are descried as ____________, ___________, or __________ in regard to their effects cell membrane
isotonic, hypotonic, or hypertonic
Most of the body's osmosis occurs in the:
kidneys
The membrane contains:
lipids, proteins, and carbohydrates
The cell Membrane contains ______________, ____________, and ________________.
lipids, proteins, and carbohydrates.
Cytoplasm
surrounds the nucleus.
Membrane Transport: Freely permeable
Any substance can cross without difficulty
What are the building blocks of molecules?
Atoms
Anchoring Proteins
Attach the cell membrane to other structures an stabilize its position Example: Inside the cell, anchor proteins bind to the cytoskeleton. Outside the cell, anchor proteins attach the cell to extracellular protein fibers or to another cell
Interstitial Fluid
Extracellular fluid between the cells and outside the vascular bed. (i.e. connective tissue, cartilage, and bone)
Hydrophobic
Fatty substances; insoluble in water; positioned on the inside; tails will not associate with water or charged molecules which enables the cell membrane to act as a selective physical barrier.
Carbohydrates
Form complex molecules with proteins and lipids on the outer surface of membrane -Function as cell lubricants and adhesives -Act as receptors for the extracellular compounds -Form part of a recognition system that keeps the immune system from attacking the body's own cells
Hydrophilic
H20 core and glycerol; soluble in water; positioned on the outside
Recognition (Identifier)Proteins
Identify a cell as self or non-self, normal or abnormal, to the immune system Example: One group of such recognition proteins is the major histocompatibility complex (MHC) (Lymphocytes)
Cell Structure: Organelles
Intracellular structures of a cell
Cell Structure: Cytosol
Liquid division of a cell
Tonicity
Measurement/rat used for effective osmolarity Refers to blood
Membrane Transport: Passive Processes
Move ions or molecules across the cell membrane without energy expenditure by the cell (Diffusion and Osmosis)
Membrane Transport: Osmosis
Net movement of H2O through a semi-permeable membrane(Water specific diffusion) -Osmosis occurs across a selectively permeable membrane that is freely permeable to water but is not freely permeable to solutes. -In osmosis, water flows across a membrane toward the solution that has the higher concentration of solutes, because that is where the concentration of water is lower. -Most of the body's osmosis occurs in the kidney
Membrane Transport: Impermeable
Nothing can cross a membrane
Movement across the membrane can be ____________ or __________.
Passive or active
Membrane Transport: Selectively permeable
Permits free passage of some substances and restricts the passage of other. -Based on size, electrical charge, molecular shape, lipid solubility, or a combination of these factors. -Can be passive or active movement
_____________ are a major component of a cell membrane.
Phospholipids
Albumin
Protein produced by the liver that determines the blood's osmotic pressure
Active processes:
Require that the cell expend energy usually in the form of ATP
Active Processes
Require that the cell expend energy, usually in the energy form of ATP.
Receptor Proteins
Sensitive to specific extracellular materials that bind to them and trigger a change in a cell's activity Example: Binding of the hormone insulin to a membrane receptors increases the rate of glucose absorption by the cell
Cell Membrane
Separates the cell's contents from extracellular fluid.
Solutes
Solutions that contain a variety of dissolved materials. Solutes can be found in both intracellular and extracellular fluids.
The extracellular fluid in most tissues is called __________________.
interstitial fluid
Isotonic
iso-equal tonos-tension -solution is one that does not cause a net movement of water into or out of the cell.
Transmission electron micrographs (TEMs)
photographs of very thin sections, and they can reveal fine details of cell membranes and intracellular structures.
Scanning electron Micrographs ( SEMs)
provide less magnification but reveal the 3-D nature of cell structures. -provide a surface view of a cell, a portion of a cell, or extracellular structures rather than a detailed sectional view.
The Cell Membrane: Structural Support
Specialized connections between cell membranes, or between membranes and extracellular materials, give tissues a stable structure.
The Cell Membrane: Regulation of exchange with the environment
The cell membrane controls the entry of ions and nutrients, the elimination of wastes, and the release of secretions.
The Cell Membrane: Physical Isolation
The cell membrane is a physical barrier that seperates the inside of the cell from the surrounding extracellular fluid.
The Cell Membrane: Sensitivity
The cell membrane is the first part of the cell affected by changes in the extracellular fluid.
Cell Structure: Nucleus
The control center of the cell. Contains genetic material and directs cell activities. -Surrounded by the nuclear envelope -Communicates with the cytosol by was of nuclear pores
Membrane Transport: Concentration Gradient
The difference between high and low concentrations.
Partial Pressure
The driving force of osmosis involving gases.
Intracellular Fluid
The fluid found inside all body cells
Extracellular Fluid
The fluid found outside the cells
Osmotic Pressure
The force/flow of water movement into a solution as a result of the solute concentration.
Cell Structure: Plasma/Cell membrane
The outer boundary of a cell and has four general functions
Membrane Transport: freely permeable membrane
any substance can cross without difficulty
The outer boundary of the cells is formed by a:
cell membrane or plasma membrane
Membrane Transport: selectively permeable
cell membrane permits the free passage of some materials and restricts the passage of others.
Concentration gradient
difference between the high and low concentrations
*solutes
dissolved materials
Our model body cell is surrounded by a watery medium known as _______________.
extracellular fluid
****hypotonic
hypo-below when a cell swells up like a balloon due
Osmotic Pressure of a solution
indication of the force of water movement into that solution increases, so does it's osmotic pressure.
Isotonic to blood plasma
-Normal Saline -Lactated Ringers
Membrane Transport: Diffusion
-Proceeding "down concentration gradient" or "downhill" -Net movement of molecules from an area of relatively high concentration to an area of relatively low concentration to affect equilibrium. -Passive process -In extracellular fluids of the body, Water and dissolved solutes diffuse freely -Some substances can pass through easily, whereas others cannot penetrate the membrane at all
Normal Saline=
0.9% NaCL (gm/100ml=900mg of NaCL/100ml)
An ion or molecule can in diffuse across the lipid portion of the membrane in one of two ways:
1. By moving across the lipid portion of the membrane 2. By passing through a channel protein in the membrane.
Cell theory has four basic concepts:
1. Cells are the building blocks of all plants and animals. 2. Cells are the smallest functioning units of life. 3. Cells are produced through the division of pre-existing cells. 4. Each cell maintains homeostasis.
Two Types of Passive Processes:
1. Diffusion 2. Filtration
Two most common methods used to study cell and tissue structures
1. Light microscopy 2. Electron microscopy
Three chacteristics of osmosis are important to remember:
1. Osmosis is the diffusion of the water molecules across a membrane. 2. Osmosis occurs across a selecvively permeable membrane that is freely permeable to water but not freely permeable to solutes. 3. In Osmosis, water flows across a membrane toward the solution that has higher concentration of solutes, because that is where the concentration of water is lower.
General functions of the Cell Membrane:
1. Physical Isolation 2. Regulation of exchange with the environment. 3. Sensitivity 4. Structural Support
The phospholipids in a cell membrane lie in two distinct layers:
1. hydrophilic 2. hydrophobic
Whether or not a substance can cross the cell membrane is based off what 5 factors?
1. size 2. electrical charge 3. molecular shape 4. lipid solubility 5. some combination of these (above) factors
Cell Theory includes the following four concepts:
1.Cells are the building blocks of all plants and animals 2. Cells are the smallest functioning unit of life 3. Cells are produced through the division of pre-existing cells 4. Each cell maintains homeostasis
Phospholipids: Lie in two distinctive layers
1.Hydrophilic: H20 core and glycerol; soluble in water; positioned on the outside 2.Hydrophobic: Fatty substances; insoluble in water; positioned on the inside; tails will not associate with water or charged molecules which enables the cell membrane to act as a selective physical barrier.
Cell Structure: The 4 General Functions:
1.Physical isolation: physical barrier that separates the inside of the cell from the surrounding extracellular fluids. 2.Regulation of exchange with the environment: Controls the entry of ions and nutrients, the elimination of wastes and the release of secretions. 3.Sensitivity: First part of the cell affected by changes in the extracelular fluid through a variety of receptors. 4.Structural support: Specialized connections between cell membrane, or between membranes and extracellular materials, give tissues a stable structure
5 Factors that determine the rate of diffusion:
1.Relative concentration 2.Barriers or decreased permeability (membrane involvement) 3.Speed or energy of motion 4.Heat-(expands) 5.Size of particle
D5W=
5gm/100ml=5gm dextrose/100ml water
The cell membrane is thin and delicate, and ranges from ____nm to ____nm in thickness
6-10nm
The cell membrane is extremely thin and delicate and ranges from ______nm-______nm in thickness.
6nm-10nm
Carrier Proteins
Bind and transport solutes across the cell membrane This process may or may not require energy Example: Carrier proteins bring glucose into cytoplasm and also transport sodium, Potassium, and calcium ions into and out of the cell
Hemolysis
Bursting of a RBC
Proteins
Can cross over the surface or in the membrane -Function to assist the chemical activities that occur withing the cytoplasm -Uptake of environment -Transport out of the cell -Cell identifiers-related to blood type
Enzymes
Catalyze reactions in the extracellular fluid or within the cell Example: Dipeptides are broken down into amino acids by enzymes on the exposed membranes of cells that line the intestinal tract
What are the building blocks of the human body?
Cells
Cells= _______ water; _____ dissolved materials(_____Saline); 99% of fluid is reabsorbed, remaining _____ in tissues return through Lymphatic system
Cells= 91.5% water; 8.5% dissolved materials (0.9% Saline); 99% of fluid is reabsorbed, remaining 1% in tissues return through Lymphatic system
Channel Proteins
Central pore, or channel, permits water, ions, and other solutes to bypass lipid portion of cell membrane Example: Calcium ion movement through channels is crucial to muscle contraction and the conduction of nerve impulses
Cell Structure: Cytoplasm
Contents of the cell, Fluid and sub cellular parts that surrounds the nucleus.
Isotonic Solution
Does not cause a net movement of water into or out of a cell. Equilibrium exists; cells will survive.
Membrane Transport: Permeability
The property of the cell membrane that determines precisely which substances can enter or leave the cytoplasm.
Hydrostatic Pressure
The pushing against a fluid that prevents the entry of a water molecule
Crenation
The shrinking of a red blood cell
Cytology: The study of the structure and function of cells.
The study of the structure and function of cells.
Hypotonic Solution
Water flows into a cell which causes it to swell up like a balloon. Cell may eventually burst, or lyse
Hypertonic Solution
Water flows out of a cell Shrivel and dehydrate
Electron microscopy
a technique that replaced light with a focused beam of electrons.
Nucleus
control center for cellular operations.
Passive processes
move ions or molecules across the cell membrane without any energy expenditure by the cell.