Cell Differentiation
Process cells undergo to become specialized.
Cells with highly developed function, often lack other properties.
Example: cell function: movement → cell will lack hormone production function
- Cells with a similar embryonic origin or function are often organized into larger functional units called tissues,
- and these tissues in turn associate with other, dissimilar tissues to form the various organs of the body.
How many chief cellular functions exist?
8 Chief Cellular Functions
- Movement
- Conductivity
- Metabolic absorption
- Secretion
- Excretion
- Respiration
- Reproduction
- Communication
Cell Function Movement
- Muscle cells generate forces producing motion
- Attached to bones → limb motion
- In hollow tubes → move/empty content when contracted
Example: smooth muscle cells surrounding blood vessels → change diameter of vessel
contraction of muscle wall in bladder → expel urine
Cell Function Conductivity
- Nerve Cells (chief function)
- Manifested as wave of excitation as a response to a stimulus
- Electrical potential that passes along surface of cell to reach it’s other parts
Cell Function Metabolic Absorption
- Intestine / Kidney (chief cell function)
- All cells take in and use nutrients from their surroundings
Example:
- Kidney tubules reabsorb fluid and synthesize proteins.
- Intestinal epithelial cells reabsorb fluids & synthesize protein enzymes.
Cell Function Secretion
- Adrenal gland / Testis / Ovaries → hormonal steroids
- Mucous gland cells → absorb substances then synthesized into new substance to serve as needed elsewhere.
Cell Function Excretion
- All cells can rid themselves of waste products
- Waste products are results of metabolic break down of nutrients
- Lysosomes (membrane bround sacs) contain enzymes that break down, digest large molecules
- Waste is released from the cell
Cell Function Respiration
- Cells absorb O2
- O2 used to transform nutrients into ATP
- Cellular Respiration or Oxidation occurs in the mitochondria
Cellular Function Reproduction
- Tissue growth occurs as cells enlarge and reproduce themselves
- Tissue maintenance requires new cells be produced to replace cells lost through cellular death
- Not all cells are capable fo continuous division
Cellular Function Communication
(book info)
Vital for cells to survive.
Constant communication allows for dynamic steady state.
Example: Pancreatic cells secrete insulin necessary to signal muscle cells to absorb sugar from blood for energy.
Discuss Epithelial Tissue
- Epithelial tissue forms sheets that:
- cover the body’s outer surface,
- line internal surfaces, and
- form glandular tissue.
- It is supported by
- a basement membrane,
- is avascular, and
- must receive nourishment from capillaries in supporting connective tissues.
Discuss Connective Tissue
- Connective tissue is the most abundant tissue of the body.
- Found in a variety of forms:
- ranging from solid bone to
- blood cells that circulate in the vascular system.
Discuss Muscle Tissue
- Muscle tissue contains actin and myosin filaments that allow it to contract and provide locomotion and movement of:
- skeletal structures (skeletal muscle),
- pumping of blood through the heart (cardiac muscle),
- and contraction of blood vessels and visceral organs (smooth muscle).
Discuss Nervous Tissue
- Consists of two cell types
- nerve cells or neurons and
- glial or supporting cells,
Distributed throughout the body, and serves as the body’s communication system.
The nervous system is divided anatomically into:
- CNS
- brain and
- spinal cord
- Peripheral nervous system (PNS),
- nerve tissue outside the CNS.
