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Name factors that affect the rate of diffusion

○ Molecular Weight
○ Temperature
○ Membrane Permeability
○ Pressure
○ Dreection of Fluid Flow
○ Concentrations


What are the 2 main types of endocytosis?



Describe endocytosis

Endocytosis: substance that are too large to pass through the cell membrane are transported across by a process called endocytosis


Describe Phagocytosis

Involves ingestion of large particles by the plasma membrane

The membrane attaches itself to the particle and vaginates outwardly and completely engulfs the object

The phagocytic vesicle is pinched off the cell wall and moves to the interior of the cell


Explain the process of active transport and its importance in biological systems.

• Some substances that are impermeable and must be pumped across the membrane since they are needed for metabolic processes
• Active transport proteins are molecular pumps that pump molecules against a concentration gradient
• These pumps require energy from ATP


Define Atrophy

Shrinkage in the size of the cell by loss of cell substance is known as atrophy.


What are causes of atrophy?

· Decreased workload
· Loss of innervation
· Diminished blood supply
· Inadequate nutrition
· Loss of endocrine stimulation
· Aging


Define Hypertrophy

Hypertrophy refers to an increase in the size of cells and, with such change, an increase in the size of the organ. The hypertrophied organ has no new cells, just larger cells


Define Hyperplasia

Hyperplasia constitutes an increase in the number of cells in an organ or tissue, which may then have increased cell volume.


What can Hyperplasia be divided into? (2)

1. Physiologic hyperplasia which can be further divided into hormonal and compensatory. An example of hormonal hyperplasia is the proliferation of the glandular epithelium of the female breast at puberty and during pregnancy. An example of compensatory hyperplasia is that which occurs when a portion of the liver is removed.
2. Pathologic hyperplasia instances of excessive hormonal stimulation or the effects of growth factors on target cells.


Define Necrosis

There are two morphological patterns of cell death, necrosis and apoptosis. Necrosis is the more common type of cell death after exogenous stimuli, occurring after such stresses as ischemia and chemical injury, and is manifested by severe cell swelling or cell rupture, denaturation and coagulation of cytoplasmic proteins, and breakdown of cell organelles.


Define Apoptosis

Apoptosis is a more regulated event. It is designed for the normal elimination of unwanted cell population during embryogenesis and various physiologic processes. There is some overlap between these two processes.


What are causes of cell injury?

Physical Agents
Chemical Agents and Drugs
Infectious Agents
Immunologic reactions
Genetic derangements
Nutritional imbalances

see p. 34 for details**


What is Hypoxia?

d) Hypoxia: Most common cause of cell injury, impacts on aerobic oxidative respiration. Loss of blood supply (ischemia), which occurs when arterial flow is imbedded is the most common cause of hypoxia. Another cause is inadequate oxygenation of the blood due to cardiorespiratory failure. Loss of the oxygen carrying capacity of the blood, as in anemia or carbon monoxide poisoning is a third less frequent basis for oxygen deprivation. Depending on the severity of the hypoxic state, cells may adapt, undergo injury, or die.


What are physical agents?

Physical Agents: Physical agents include mechanical trauma, extremes of temperature (burns and deep cold), sudden changes in atmospheric pressure, radiation, and electric shock.


What are Infectious agents?

These agents range from submicroscopic viruses to large tapeworms.


What are genetic derangements?

Genetic derangements: The genetic injury may result in congenital malformations or in subtle alterations in the coding of hemoglobin S in sickle cell anemia.


Give examples of symport and antiport active transport systems.

Symport: two molecules move simultaneously in the same direction

Antiport: two molecules move simultaneously in opposite direction.


What is the smallest functional unit in the body?



How many distinguishable cell types are there?

more than 200


Similar cells are organized into _____.



Different tissues are organized into _______.



Several different organs combine to perform a more extensive functions and are then referred to collectively as____________.

Organ System


What are the basic requirements of every cell?

Obtain materials ( required for growth, maintenance and reproduction of the cell) and a source of energy ( for the performance of all kinds of work)


What are the 3 main components of cells?

1- Nucleus
2- Cytoplasm
3- Cell Membrane


True or False?
The nucleolus is always singe

Can be single or multiple, and its role is to synthesize and assemble the RNA molecules and numerous proteins that make up the ribosomes


What are the roles of the nucleus?

- Store genes on chromosomes
- Organize genes into chromosomes to allow cell division
- Transport regulatory factors and gene products via nuclear pores
- Produce messages
- Produce ribosomes in the nucleolus
- Organze the uncoiling of DNA to replicate and decode key genes


True or False
The nucleus is the control centre of the cell?

it determines what is synthesize, how much is synthesized, and how it is synthesized.


Which part of the Endoplasmic Reticulum is covered with ribosomes?

The Rough ER


Is the ER structurally continuous of the outer membrane of the nuclear envelop?