Cell Types and Modification PDF

Cell types and cell modification CELL 🡪 Cells grow, mature, and undergo differentiation in multicellular animals. Tissues are formed as a result of cell differentiation. The human body, for example, is made up of more than 200 differentiated cells. A tissue is a group of similar cells tha...

Cell types and cell modification CELL 🡪 Cells grow, mature, and undergo differentiation in multicellular animals. Tissues are formed as a result of cell differentiation. The human body, for example, is made up of more than 200 differentiated cells. A tissue is a group of similar cells that performing a common function. 🡪The study of animal and plant tissues is called histology. Histology involves the preparation of thin tissue sections, differentially stained and examined under the microscope TYPES OF CELLS IN A HUMAN BODY STEM CELLS This type of cells can divide and create to another type of cells (Bone cells, epithelial cells, etc.) BONE CELLS This type of cells can entirely produce and repair bones inside the body. 3 types of bone cells. 1. OSTEOCLASTS - DISSOLVES bones 2. OSTEOBLAST - CREATES new bones 3. OSTEOCYTES - HELPS TO COMMUNICATE with other bones in the body BLOOD CELLS RED BLOOD CELLS (RBC) Components of blood cells 1. White Blood Cells (WBC) - Granulocytes, Monocytes and Lymphocytes 1.1 NEUTROPHILS - helps to do PHAGOCYTOSIS 1.2BASOPHILS - helps to produce enzymes PATHOGENS 2. PLATELETS - helps to produce blood clot. MUSCLE CELLS Also known as MYOCYTES, these are long and tubular cells and support internal organ functions. Support the function - PERISTALSIS SEX CELLS These types of cells are responsible for producing new offspring. OOGENESIS SPERMATOGENESIS FAT CELLS This is responsible for producing and storing fats a clustered manner. Adipose tissues NERVE CELLS This is responsible for communicating and relaying message from and to the entire body. Neurons EPITHELIAL CELLS This is responsible for communicating and relaying message from and to the entire body. Epithelial cells 1.1 Epithelium 1.2 Endothelium 1.3 Mesothelium CARTILAGE CELLS The primary cell that makes cartilage is the chondrocyte, which resides within the lacunae. The cartilage matrix consists of fibrous tissue and various combinations of different tissues. TYPES OF TISSUES 🡪A microtome is an instrument used to cut tissues into ultrathin sections. Tissue sections are treated with biological stains (dyes) to differentiate cells and tissues and to have a clearer view of the different parts under the microscope. TYPES OF TISSUES 🡪There are four types of tissues found in animals: epithelial, connective, muscular, and nervous. These different types of tissues have distinct structures and functions. An organ is made up of different types of tissues. The stomach, for example, is made up of four types of tissue. The inner wall of the stomach is lined by columnar epithelial cells for absorption of digested food. The stomach is surrounded by smooth muscle tissues that are responsible for the movement (peristalsis) during digestion. The stomach walls also contain nervous tissues (nerves) that transmit signals to and from the brain. Blood, a type of connective tissue, is responsible for the transport of nutrients from absorbed food. EPITHELIAL TISSUES COVER 🡪Animals are multicellular organisms, which means that their bodies are composed of many cells. Animal cells are organized into specialized groups with distinct functions that form different tissues. In most animals, different organs form organ systems. 🡪Epithelial tissues may be simple or stratified. A simple epithelium is made up of a single layer of cells. A stratified epithelium has more than one layer of cells. There are three types of epithelium based on their shape-squamous, cuboidal, and columnar. EPITHELIAL TISSUES COVER 🡪The Simple squamous epithelium consists of a single layer of flattened cells. These flattened cells are usually found in thin barriers where exchange of nutrients, wastes, and respiratory gases occur. They are found in the alveoli of the lungs where gas exchange takes place, and in capillaries where diffusion and osmosis take place. 🡪Simple cuboidal epithelium is a single layer of cube-shaped cells. Cuboidal cells have larger cytoplasm compared to squamous cells, thus, they can perform more complex functions such as absorption and secretion. 🡪Pseudostratified epithelium, as the name implies, is the “falsely stratified” epithelium. It is made up of columnar cells that are tall and thin and form irregular shapes. CONNECTIVE TISSUES CONNECT 🡪Connective tissues include a large group of different tissues characterized by having dispersed cells and large extracellular space called extracellular matrix. The extracellular matrix includes protein fibers (collagen, elastic, or reticular) and ground substances secreted mostly by the cells of the connective tissue. The extracellular matrix may be solid (bone), soft (connective tissue), or liquid (blood). Other function; 1. Protection 5. Storage of fats 2. Provision of cushion 6. Transport of nutrients and wastes 3. Maintenance of body form 7. Body defense 4. Filling body space 8. Repair of body parts CONNECTIVE TISSUES CONNECT Connective Tissue Proper – also called areolar connective tissues, it is a type of connective tissue with watery matrix (ground substance) where cells, mostly fibroblasts, are located. Special white blood cells, called macrophages can also be found in the matrix. Supportive Connective Tissue – Separated by a strong yet flexible matrix made up of a substance called chordin, a protein-carbohydrate complex. Fluid Connective Tissue –Blood is a special type of connective tissue with a liquid matrix called the blood plasma. Blood is responsible for transporting RBC and WBC, removes carbon dioxide and other wastes. Muscular Tissues Contract 🡪Muscular tissues are contractile tissues responsible for movement. The muscle cells (or more accurately called muscle fibers) that make up muscle tissues contain myosin and actin, proteins involved in muscle contraction. There are three types of muscular tissues: skeletal, cardiac, and smooth. 🡪Skeletal muscular tissues, as the name implies, are attached to bones through tendons. They are responsible for the movement of most body parts and for locomotion. Nervous Tissue Conduct Nervous Tissue Conduct 🡪The nervous tissue is made up of nerve cells called neurons, which are found in the brain and spinal cord. Neurons are specialized cells that conduct impulses to and from the brain. A typical neuron is made up of three parts: dendrites, cell body, and axon. Dendrites receive impulses and send them to the cell body. The cell body is like a typical cell where the nucleus and organelles are found. The axon is a long fiber like part that transmits the impulses away from the cell body to the next neuron. Tissues Form Organs and Organ Systems 🡪 Tissues are groups of similar types of cells that perform diverse similar functions, A group different tissues united to perform a common function forms an organ. Tissues Form Organs and Organ Systems CELL MODIFICATION Cell Modifications What are cell modifications? Are specialized or modifications reacquired by the cell after cell division, this means common cell parts that are found in cells before cell division cannot be considered a cell modification It helps the cell in different beneficial ways such as efficient functioning and promotion of organism survival Three types based on location; Apical Lateral Basal Epithelial Tissue Apical Modification 1. Apical Modification Cell modification found on the apical surface of the cell 1a- 1b. Cilia and Flagella Cilia are usually short, hair-like structures that move in waves Flagella are long whiplike structures formed from microtubules Apical Modification 1c-1d. Villi and Microvilli Villi are finger-like projections that arise from the epithelial layer in some organs. They help to increase surface area allowing for faster and more efficient adsorption Microvilli are smaller projections that arise from the cell's surface that also increase surface area allowing faster and more efficient absorption Apical Modification 1c-1d. Villi and Microvilli Villi are finger-like projections that arise from the epithelial layer in some organs. They help to increase surface area allowing for faster and more efficient adsorption Microvilli are smaller projections that arise from the cell's surface that also increase surface area allowing faster and more efficient absorption Apical Modification 1e. Pseudopods Temporary, irregular lobes formed by amoebas and some other eukaryotic cells Bulge outward to move the cell or engulf prey 1f. Extra Cellular Matrix (ECM) Compound secreted by the cell on its apical surface Cell wall is the extracellular structure in plant cells that distinguishes them from animal cells Glycoprotein is the main ingredient of ECM in animal cells Lateral Modification Tight Junction Act as barriers that regulate the movement of water and solutes between epithelial layers Prevents leakage of extracellular fluid 2b. Adhering Junction Anchoring junction on the lateral surface of the cell Very similar to the anchoring junction of the basal surface of the cell Fasten cells to one another Lateral Modification 2c. Gap Junction Also known as communicating junctions closable channels that connect the cytoplasm of adjoining animal cells allows direct exchange of chemicals between the cytoplasm of two cells Basal Modification 3a. Desmosomes/Hemidesmosomes Anchoring junction on the basal surface of the cell Rivet-like links between cytoskeleton and extracellular matrix components such as the basal lamina that underlie epithelia Primarily composed of keratin, integrins and cadherins