Human Cell and Human Body Tissue PDF - 2024-2025

Human Cell and Human Body Tissue  Objectives The students will be able to: State the basic principles of cell theory. List the types of cells. Differentiate between the structure of prokaryotic cells and that of eukaryotic cells. Identify the components of animal cell and state the funct...

Human Cell and Human Body Tissue  Objectives The students will be able to: State the basic principles of cell theory. List the types of cells. Differentiate between the structure of prokaryotic cells and that of eukaryotic cells. Identify the components of animal cell and state the function of each. Differentiate between animal cell and plant cell. List the four types of tissue and provide a general function for each.  What is a cell? ▪ A cell is defined as the smallest, basic unit of life that is responsible for all of life’s processes. ▪ Every living thing has cells such as bacteria, protozoa, fungi, plants, and animals. ▪ All the chemical reaction in the cell keeps the living organism alive. ▪ Some organisms are made up of only one cell (unicellular) like bacteria and protozoa, other organisms are made up of many cells (multicellular) like animals and human.  Discovery of Cells ▪ The cell was first discovered by Robert Hooke in 1665, by using a microscope to examine a thin slice of cork. ▪ What he saw looked like small boxes, so he called them “cells”.  The Cell Theory The principle of the cell theory: ▪ All living organism are made up of cells. ▪ Cell is the structure and function unit of all living organisms. ▪ All cells come from pre-existing cells by division.  Types of Cells There are two types of cells: 1. Prokaryotic cells. 2. Eukaryotic cells. Prokaryotic Cells ▪ No nucleus. ▪ DNA present in nucleoid region. ▪ No membrane bounded organelles. ▪ They are usually unicellular organism. ▪ Example: Bacteria Eukaryotic Cells ▪ They have nucleus. ▪ DNA found within membrane bound nucleus. ▪ Contain organelles surrounded by membrane. ▪ They are usually multicellular organism. ▪ Example: plant and animal cells.  The Difference between Prokaryotic and Eukaryotic Cells Prokaryotic Cell Eukaryotic Cell No nucleus They have nucleus DNA present in nucleoid DNA found within region membrane bound nucleus No membrane bounded Contain organelles organelles surrounded by membrane Usually, unicellular organism Usually, e.g., Bacteria multicellular o rganism e.g., plant and animal cells.  Structure of Animal Cell ▪ The animal cell as seen via electron microscope are composed of: A. Plasma Membrane B. Cytoplasm C. Organelles These organelles are specialized structure surrounded by its own membrane and perform specific function. They include: 1. Nucleus 2. Endoplasmic reticulum 3. Ribosome 4.Golgi apparatus 5. Mitochondria 6. Lysosomes 7. Centrosome 8.Vacuoles Animal cell Structure A. Plasma Membrane ▪ It is a gateway to the cell. ▪ The plasma membrane is a biological membrane that separates the interior of the cell from the outside of the cells (the extracellular space). ▪ One thing that all cells have in common is a plasma (cell) membrane. ▪ It surrounds the cell and acts as a barrier between the inside and the outside of a cell. A. Plasma Membrane ▪ Structure: It consist of phospholipid bilayer in which protein molecules are embedded. Short chains of sugars are attached to the outer surface of one protein and lipid molecules. Phospholipids have a hydrophilic (water loving) phosphate head and hydrophobic (water fearing) fatty acid tails. ▪ Function: It allows some substance but not all to move in and out of the cell which is called selective permeability.  B. Cytoplasm ▪ The cytoplasm is an essential component of the cell. It is mainly composed of water, salts, and proteins. ▪ It is a semi-liquid jelly-like material, that fills the cell between the cell surface membrane and the nucleus. ▪ All the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are in the cytoplasm. Organelles : 1. Nucleus The nucleus is a highly specialized organelle that serves as the information and control center of the cell. ▪ Structure: The nucleus is surrounded by a double membrane called the nuclear envelope. Contains one or more nucleoli. Contains complex of proteins and DNA called Chromatin. ▪ Function: Controls cell activities. Essential for cell division. 2. Ribosomes ▪ A ribosome is a complex molecular machine found inside the living cells that produce proteins from amino acids during a process called protein synthesis. ▪ Structure: Small particle exist freely in cytoplasm or attached to the surface of Rough Endoplasmic Reticulum. Ribosome synthesized in the nucleolus and is completed in the cytoplasm. ▪ Function: Synthesis of protein. 3. Endoplasmic Reticulum (ER) ▪ The endoplasmic reticulum (ER) is a large, dynamic structure that serves many roles in the cell including calcium storage, protein synthesis and lipid metabolism. ▪ Structure: Endoplasmic Reticulum is a complex network of tubular membranes closely packed together and continuous with nuclear membrane. It is present in the cytoplasm of the eukaryotic cell. ▪ Thera are two types: Rough Endoplasmic Reticulum. Smooth Endoplasmic Reticulum. 3. Endoplasmic Reticulum (ER) 1. Rough endoplasmic reticulum Ribosomes attached to surface​ ▪ Function : Synthesis of proteins​ 2. Smooth Endoplasmic Reticulum No attached ribosomes​ ▪ Function : Synthesis of lipids.​ Detoxification of harmful substances in the cell.​  4. Golgi Apparatus ▪ Structure: Vacuolar region surrounded by a complex meshwork of vesicle budding off at its end. ▪ Function: The Golgi apparatus processes, packages proteins formed by rough ER and transport them to other parts of the cell. 5. Mitochondria ▪ Mitochondria are membrane-bound cell organelles (mitochondrion , singular) that generate most of the chemical energy needed to power the cell's biochemical reactions. Rod shape with a double membrane. ▪ Structure: Outer membrane is smooth and regular while inner membrane is folded to form crista. Have their own DNA. ▪ Function: The powerhouse of the cell, it releases energy as it is the site for cellular respiration. 6. Lysosome ▪ A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes are involved with various cell processes. ▪ Structure: Membrane bound vesicle. Contain digestive enzymes. ▪ Function: Aid in cell renewal. Break down old cell parts. Digests invaders. 6- Lysosome Function Mechanism 7. Centrosome ▪ A centrosome is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell which provides structure of the cell. ▪ Structure: Consist of two cylindrical body structure called centrioles arranged at right angles to one another. ▪ Function: Play an important role in cell division 8. Cytoskeleton ▪ The cytoskeleton is a structure that helps cells maintain their shape and internal organization, and it also provides mechanical support that enables cells to carry out essential functions like division and movement. ▪ It is made of three types fibers: 1. Microfilaments. 2. Microtubules. 3. Intermediate filaments. ▪ Function: 1. Mechanical support. 2. Maintain cell shape. 3. Help in movement of cell parts. Plant cell Plant cell Structure Structure of Plant Cell ▪ Plant cells are eukaryotic cells present in green plants. ▪ The plant cell is surrounded by a cell wall which is involved in providing shape to the plant cell. There are other organelles that are associated with different cellular activities. ▪ Although there are many similarities between animal and plant cells, differences exist: Centrosome are absent in plant cells. Plant cells have a cell wall and chloroplast which are not found in animal cells. Vacuoles are large in plant cell , small and temporary in animal cell. Differences Between Animal Cell and Plant Cell Animal Cell Plant Cell Size Smaller Larger Cell Wall Absent Present Chloroplast Absent Present Centrosome Present Absent Vacuoles Small and temporary Large Cell Wall ▪ Structure : A rigid fully -permeable protective layer in plant cell. Surrounds the cell surface membrane. Plant cell wall is composed of cellulose. ▪ Function: Protect the cell from injury. Gives the plant cell a fixed shape Chloroplast ▪ Structure : Chloroplasts are commonly found in plant cells. Chloroplasts are oval-shaped and have two membranes: an outer membrane and an inner membrane. Chloroplast contain a green pigment called Chlorophyll. ▪ Function: Chlorophyll is essential for photosynthesis process, the process by which plants make its own food. Vacuoles ▪ Structure : The term “vacuole” means “empty space”. A vacuole is a membrane bound structure found in the cytoplasmic matrix of plant cell. Plant cell usually have a large central vacuoles which contains a liquid cell sap. Cell sap contains dissolved substances such as sugars, mineral salts and amino acids. ▪ Function: Stores salts, minerals, pigments and proteins within the cell. Human Body Tissue Human Body Tissue ▪ Tissue: is defined as an identical group of cells existed in association with one another that perform a specific function in a living organism. ▪ There are four primary tissue types in the human body: 1. Epithelia Tissue 2. Connective Tissue 3. Muscular Tissue 4. Nervous Tissue 1. Epithelial Tissues ▪ Epithelial tissue covers body surfaces and lines body cavities. ▪ Epithelial tissues can be subdivided according to the shape and arrangement of the cells. ▪ According to shape, epithelial cells are classified as: 1. Squamous (flat) 2. Cuboidal (cube- shaped) 3. Columnar (taller than they are wide) 4. Transitional ▪ According to arrangement of cells, epithelial tissue can be classified as: 1. Simple ( consists of a single layer of cells). 2. Stratified ( consists of many layers of cells). 1. Epithelial Tissues ▪ Locations: They cover the exposed surface of the internal organs of the body. They line the internal organs of the body, such as intestine and urinary bladder. They constitute the secretory portions of all glands, such as sweat and thyroid glands. 1. Epithelial Tissues Functions: 1. Protection It is the first line of defense against any kind of mechanical injury, chemical exposure, excessive fluid loss and infections. 2. Absorption The epithelial lining of the digestive tract absorbs water and nutrients. 3. Exchange of substances It regulates the exchange of substances between body and external environment. 4. Secretion Various glands made up of epithelial cells secrete hormones, enzymes, saliva, mucus and sweat. 2. Connective Tissue ▪ Connective tissue is the most abundant primary tissue in the body and has a variety of functions. ▪ The tissue is never found on the external surfaces of the body or organs. ▪ Connective tissue is made up of two main components: Cells and extracellular matrix. 1. Cells Cells Cells Fibrocytes Mast cells Macrophages Plasm cells Fat cells WBCs 2. Connective Tissue 2. Extracellular Matrix: ▪ Connective tissue matrix is composed of ground substance and fibers. Ground substance: fluid, gel, between cells and fibers. Fibers: 1. Collagen fibers. 2. Elastic fibers. 3. Reticular fibers. Types of Connective Tissues Areolar tissue Types of Connective Tissues Loose Connective tissue Dense Connective tissue Adipose tissue Cartilage Bone Blood Types of Connective Tissue Function of Connective Tissue 1. Binding and supporting different parts of our body. 2. Protection. 3. Insulating. 4. Storing Energy. 5. Transporting substance within the body. 3. Muscular Tissue ▪ Muscle tissue is found everywhere in the body, Not only just beneath the skin but also deep within the body. ▪ It is composed of elongated muscle cells, which are called muscle fibers. ▪ There are three different types of muscle tissue: 1. Skeletal muscles : it is responsible for voluntary movement of our body, example: Leg, and arm muscles. 2. Cardiac muscles : it is found only in the wall of the heart. Contraction of this muscle helps in pumping of blood throughout our body. 3. Smooth muscles: it is present in the wall of hollow organs, example: muscle in the wall of stomach and blood vessels. Types of Muscular Tissue 4. Nervous Tissue ▪ Nervous tissue is the term for groups of organized cells in the nervous system, which is the organ system that controls the body’s movements, sends and carries signals to and from the different parts of the body. ▪ Nervous tissue is made of two cell types: Neurons or nerves: that transmit electrical impulses. Neuroglia: supporting, nourishing and protecting neurons. Thank You