Tissues and Cell Modifications PDF

Tissue Structure and Function  Objectives 1. Illustrate the different types of cells in the body 2. Describe Cellular modifications that allow them to carry out specific conditions. 3. Discuss some specialized cells and their functions. 4. Draw and familiarize...

Tissue Structure and Function  Objectives 1. Illustrate the different types of cells in the body 2. Describe Cellular modifications that allow them to carry out specific conditions. 3. Discuss some specialized cells and their functions. 4. Draw and familiarize yourself with the different tissues and cell modifications.  Tissue An aggregation of cells and cell products of similar structure and embryonic origin that perform a common function  Histology The study of tissues, especially their structure and arrangement  Basic Tissue Types Epithelial Connective Muscle Nervous  Organ An aggregation of tissues organized into a functional unit  System Organs working together as functional units  Epithelial Tissue Sheet-like layer of cells Cover surfaces or line cavities Often has glandular cells for fluid secretion Endothelium Epithelium that lines heart, blood vessels and lymphatic vessels  Locations of Epithelial Tissues Covers the body (epidermis) Found on the inside of hollow organs and the outside of all organs Found above a connective tissue layer (epi = above) Lines the cavities, tubes, ducts, and blood vessels inside the body  Three Basic Shapes Squamous – like scales, or pancakes (“being squashed like a pancake”) Cuboidal – looks like cubes Columnar – longer and look like columns  Epithelial Types Simple Epithelium Simple squamous – inside blood vessels Simple cuboidal – lines ducts, ex. Kidney tubules, mucous glands Simple columnar – lining of small intestine Pseudostratified Columnar – trachea, bronchi FUNCTIONS OF EPITHELIAL CELLS Protects from physical & chemical injury Protects against microbial infection Contains nerve endings which respond to stimuli Filters, secretes & reabsorbs materials Secretes fluids to lubricate joints Figure 09.9a Figure 09.9b Pseudostratified Columnar  Epithelial Types Stratified Epithelium Stratified squamous - skin Transitional – urinary tract and bladder  Connective Tissue Tissue that connects Loose connective tissue adipose (fat) Dense connective tissue cartilage Bone Vascular tissue Erythrocytes: Red Blood Cells – carry oxygen Leucocytes: White Blood Cells – part of the immune system Platelets - clotting Adipose Figure 09.11c Figure 09.11d Erythrocytes: Red Blood Cells Leucocytes: White Blood Cells Platelets  Muscle Tissue Types Smooth Muscle (=Involuntary Muscle) Ex. Small intestine Skeletal Muscel (=Voluntary Muscle) Ex. Large muscles of body Cardiac Muscle Skeletal Smooth Cardiac Muscle fiber Sliding Filament Theory  Nervous Tissue Includes Nerves, Spinal Cord, Brain Cells are called neurons Function Of Nervous Tissue Neurons generate and carry out nerve impulses. They produce electrical signals that are transmitted across distances, they do so by secreting chemical neurotransmitters. Responds to stimuli Carries out communication and integration Provides electrical insulations to nerve cells and removes debris Carries messages from other neurons to the cell body Three basic types of neurons are123: Sensory neurons: These neurons receive information from the external or internal environment and transmit it to the brain or spinal cord. They have long dendrites and short axons1. Motor neurons: These neurons carry signals from the brain or spinal cord to the muscles or glands. They have short dendrites and long axons1. Interneurons: These neurons connect sensory and motor neurons or other interneurons. They have short dendrites and short or long axons1.  What is Cell Modification? -are specialized or modifications reacquired by the cell after cell division that helps the cell in different beneficial ways and to help perform specific tasks.  Cell Modification Flagella – is a whiplike structure that extends from the cell body. It pushes the cell to a particular direction in a propelling motion. It is connected to the cytoplasm and contained in the cell’s plasma membrane. Flagella  Cilia - are hairlike protrusions that cover most parts of the cell. They move the cell in a vibratory style. Cilia may be motile or nonmotile Nonmotile cilia are also called primary cilia Motile cilia are mostly found covering the cell’s surface. Cilia  Tiny fingerlike structures that protrude from the cell membrane. Covered by a single layer of epithelial cells and is supplied with blood by the capillaries. Functions in assimilation, adhesion and aids in the secretion of substances. Capable of increasing the surface area of the cell because of the minute folds in it. Microvilli  Pseudopodia Temporary extensions of the cytoplasm. Pseudo – false Podia- feet- false feet Powered by a microfilament near the cellular membrane that directs them to their target food or foreign body , and in amoeba like movement , they will approach and engulf the target. Pseudopodia  Root Hairs are where most water absorption happens. They are long and thin so they can penetrate between soil particles and they have a large surface area for absorption of water. Water passes from the soil water to the root hair cell's cytoplasm by osmosis. Root Hairs