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The Cell Theory Chapter 2
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The Cell AAAAll living things are made of cells. CCCCells are the smallest living unit of life. EEEEach cell performs the necessary functions to sustain life. CCCCells can replicate themselves. Cancer occurs when cells replicate haphazzardly. CCCCellular function is carried out by organelles.
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Cellular reactions are mediated (controlled) by ENZYMES. Enzymes speed up chemical reactions. All the chemical reactions in the body make up its METABOLISM. There are 10 organelles that you are responsible for.
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Plasma Membrane Outer covering of the cell. Also called the PLASMALEMMA. Separates the intracellular (inside) fluid and the extracellular (outside) fluid. Double layer of lipids (fat) with protein molecules between the layers.
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Polar Head (like water) Non-polar tails (do not like water) Proteins within the membrane. They give support to the membrane and prevent it from collapsing. Carbohydrates are attached to the integral proteins. These form the GLYCOCALYX.
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The glycocalyx is a sticky coat that allows the cell to bind to other cells. The glycocalyx also serves as a marker. i.e.: certain antibiotics recognize the i.e.: certain antibiotics recognize the glycocalyx and attach to the cell. glycocalyx and attach to the cell.
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Functions of the Plasma Membrane Allows entry into the cell (Endocytosis) Phagocytosis – cell eating Phagocytosis – cell eating Pinocytosis – cell drinking Pinocytosis – cell drinking Receptor-Mediated - hormones Receptor-Mediated - hormones Allows movement out of cells (Exocytosis)
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Cytoplasm CCCCytosol is a gel like substance which holds all the internal cellular organelles. CCCContains ions, water, and enzymes.
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THE ORGANELLES Perform all the cellular functions. “Little Organs”
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MITOCHONDRIA Power plant of the cell Produces energy
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RIBOSOME 2222 parts that make proteins. RNA Ribosome
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ENDOPLASMIC RETICULUM Subway system of the cell. Network of membrane-walled tubes that twist through the cytoplasm. ROUGH E.R. – have ribosomes attached. SMOOTH E.R. – do not have ribosomes attached.
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GOLGI APPARATUS Stacks of disk shaped membranes. Sort Package proteins made in the ER Process
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LYSOSOMES Sacs containing digestive enzymes that can break down almost all types of biological materials.
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PEROXISOMES Contain oxidases (use oxygen to neutralize aggressive compounds known as free radicals). Free radicals can damage cellular proteins, membranes, and DNA if left to accumulate.
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CYTOSKELETON System of complex rods that run throughout the cytoplasm. Microtubules Microfilaments
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CENTROSOME Contains a matrix and an inner pair of centrioles which are important in cellular division.
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NUCLEUS Membrane bound organelle which is the control center for all cellular activity.. Contains DNA – produce instructions for protein synthesis. Contain chromosomes Produce ribsomes in the nucleolus
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Specialized Connections Between Cells - Desmosome 1 - Microvilli 2 - Zonula occludens 3 - Zonula adherens 4 - Desmosome 5 - Terminal Web 6- Interdigitation
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Related Clinical Terms NECROSIS – cellular death due to disease or injury. HYPERTROPHY – increase in size. i.e. Muscle cells become hypertrophic in response to exercise. i.e. Muscle cells become hypertrophic in response to exercise.
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nucleus Cell membrane Rough Endoplasmic reticulum mitochondria Golgi apparatus nucleolus Nuclear membrane Smooth Endoplasmic reticulum
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TISSUES Chapter Four
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OBJECTIVES for Tissues Be able to list the four basic tissue types and give examples of each. Describe the functions of each tissue type. Describe the cellular components of each tissue type. Describe and identify the morphology of epithelial tissue types.
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Tissues Cells do not operate independently. Related cells work and operate together in organized groups. The bottom line: Tissues are clubs of cellular organization.
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Four Types of Tissues 1111. Epithelial Tissue 2222. Connective Tissue 3333. Muscle Tissue 4444. Nervous Tissue
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EPITHELIAL TISSUE Covers the body surface or Lines a body cavity
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Epithelial Tissue Occurs at the interface of two different environments. i.e. The epidermis is between the inside and the outside of the body. i.e. The epidermis is between the inside and the outside of the body. Protects the body by detecting harmful stimuli. i.e. Receptors for pain are found within the skin. i.e. Receptors for pain are found within the skin.
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SSSSecretion release of molecules from the cell AAAAbsorption bringing small molecules into the cell.
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Ion transport – moves ions (charged molecules) across a membrane. The epithelium filters fluids that cross the barrier.
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Characteristics of Epithelial Tissue 1. Cellularity – composed almost entirely of cells. 2. Specialized Contacts – connects adjacent cells. gap junctions, tight junctions, desmosomes 3. Polarity – under surface called the “basement membrane”. 4. Avascular – lacks blood vessels. Receives nutrients through the underlying connective tissue
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5. Regeneration – replaces lost/dead cells quickly.
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Shapes of Epithelial Tissue Simple Epithelium – one layer Stratified Epithelium – more than one layer Squamous – cells are wider than tall Cuboidal – cells are just about as tall as wide Columnar – cells are taller than wide.
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An Illustrated View of Epithelial Types
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Simple Cuboidal Epithelium
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Simple Columnar Epithelium
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Pseudostratified Ciliated Columnar Epithelium Pseudostratified ciliated columnar epithelium with pale goblet cells. The different levels of nuclei are clearer here. Again, notice the wavy-looking cilia
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Stratified squamous epithelium with beginning surface cornification. This section is from thin skin, which has a dry surface covered with dead cells. Notice how flat the surface cells are and how dark and pyknotic (degenerative) their nuclei have become. Again, notice the distinct row of basal cells.
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CONNECTIVE TISSUE Types of connective tissue FatCartilage Ligaments and Tendons BoneBloodCollagen
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Functions of Connective Tissue 1. Support and bind other tissues. (tendons, ligaments) 2. Hold body fluids (ground substance). 3. Defend against infection - mast cells - mast cells - macrophages - macrophages - plasma cells - plasma cells - neutrophils - neutrophils 4. Store nutrients as fat.
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Mesenchyme -- embryonic c.t. with multipotential cells.
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A stretched preparation of areolar connective tissue. The pink fibers of different thicknesses are collagenous (or white) fibers. The dark, thin, more tortuous fibers are elastic (or yellow) fibers. Most of the nuclei belong to fibroblasts.
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Fat cells -- note nucleus and rim of cytoplasm pushed to one side by the accumulation of fat. The lipid itself has been dissolved out in fixation. In the center of the picture, in the space bounded by the four large fat cells, there is a small, round cross- cut of a capillary with a dark, shrunken red blood cell inside.
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Hyaline cartilage from the trachea
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BLOOD - Neutrophil - Erythrocytes 1 – Erythrocyte 2 - Neutrophil
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Muscle Tissue Brings about body movement. Moves by shortening. Three Types: 1. skeletal – pulls on long bones. Striated. 1. skeletal – pulls on long bones. Striated. 2. cardiac – only in the heart. 2. cardiac – only in the heart. 3. smooth – no visible striations. Found in walls of hollow visceral organs such as digestive system, urinary organs, blood vessels, and uterus. Mostly involuntary. 3. smooth – no visible striations. Found in walls of hollow visceral organs such as digestive system, urinary organs, blood vessels, and uterus. Mostly involuntary.
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1 -A Band 2 - Z Line3 - Intercalated disks
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1 - Multinucleated skeletal muscle fibers Skeletal Muscle Fibers
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Smooth Muscle Tissue 1 – Smooth muscle fibers 2 – Artery endothelium 3- Artery Lumen
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Nerve Tissue Uses electrical impulses to transport information. Can Regenerate
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1 - Glial cells2 - Neurons Neurons
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Identify the Following: Epidermis Dermis Hair follicle Subcutaneous fat Pore Epithelial Tissue CT Arrector Pilae Muscle Nerve Endings ALL FOUR TISSUE TYPES ARE USUALLY FOUND TOGETHER
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