Human Anatomy and Physiology 1 PDF

HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 The Tissue Level of Organization Types of Tissues WHAT IS A TISSUE? - A tissue is a group of cells that usually have a common embryonic origin in an embryo and...

HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 The Tissue Level of Organization Types of Tissues WHAT IS A TISSUE? - A tissue is a group of cells that usually have a common embryonic origin in an embryo and function together to carry out specialized activities - There are 4 basic types of tissues in the human body and they are categorized according to Cell Junctions their structure and function - Cells can be held together in a number of ways. These points of contact The 4 Tissue Types between cells are called cell junctions. - Epithelial - Connective Tight Junctions - Muscular Adherens Junctions - Nervous  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 Desmosomes EPITHELIAL TISSUE General Features of Epithelial Tissue - Cells are arranged in sheets and are densely packed - Many cell junctions are present - Epithelial cells attach to a basement membrane - Epithelial tissue is avascular but does have a nerve supply - Mitosis occurs frequently Hemidesmosomes Surfaces of Epithelial Cells and the Basement Membrane Gap Junctions Classification of Epithelial Tissue - Covering and lining epithelia are classified according to the shape of the cells and how many layers thick they are COMPARISON BETWEEN EPITHELIAL AND CONNECTIVE TISSUES EPITHELIAL vs. CONNECTIVE TISSUE Covering and Lining Epithelial Tissue - The name of the specific type of stratified epithelial tissue depends on the shape of the apical cells ▪ Table 4.1 in your textbook shows examples of each of the epithelial tissues – notice the similarities and differences! (galit yarn)  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 Epithelial Tissue Naming Combinations Structural Classification of Glandular Epithelium - Unicellular – single cells o Goblet cells - Multicellular – composed of many cells that form a distinctive microscopic structure or macroscopic organ o Sweat glands o Oil glands o Salivary glands Glandular Epithelium Multicellular Exocrine Glands - A gland is a single cell or a mass of epithelial cells adapted for secretion o The secretions of endocrine glands enter the interstitial fluid and diffuse into the bloodstream o The secretions of exocrine glands enter ducts that empty onto the surface of a covering/lining epithelium such as the skin or the lumen of the stomach Functional Classification of Glandular Epithelium  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 Connective Tissue o Elastic fibers o Reticular fibers General Features of Connective Tissue - Consists of two basic elements: 1. Cells 2. Extracellular matrix - Connective tissue cells do not have any free surfaces - Connective tissue is highly vascularized and has a nerve supply o Exceptions: tendons and cartilage Classification of Connective Tissue Connective Tissue Cells - Embryonic o Mesenchyme o Mucous Connective Tissue Extracellular Matrix - Extracellular matrix is located in the spaces between connective tissue cells - Extracellular matrix is composed of fibers and - Mature ground substance o Loose o Dense o Cartilage o Bone o Blood MEMBRANES - Membranes are flat sheets of pliable tissue that cover or line a part of the body - 2 types of membranes 1. Epithelial membranes ▪ Mucous membranes Connective Tissue Fibers ▪ Serous membranes - Fibers in the extracellular matrix provide ▪ Cutaneous membranes strength and support to a tissue 2. Synovial membranes o Collagen Fibers  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 NERVOUS TISSUE General Characteristics of Nervous Tissue - Two kinds of cells: 1. Neurons 2. Neuroglia - Most neurons have a cell body, dendrites, and axons ▪ Neurons can carry sensory or motor information and they can perform integrative functions - Neuroglia protect and support neurons MUSCULAR TISSUE EXCITABLE CELLS - Neurons and muscle fibers are General Characteristics of Muscular Tissue considered excitable cells because they - Muscle tissue consists of fibers that provide exhibit electrical excitability motion, maintain posture, and produce heat ▪ Electrical excitability is the ability - 3 types of muscle tissue: to respond to certain stimuli by 1. Skeletal muscle producing electrical signals, 2. Cardiac muscle such as action potentials, which 3. Smooth muscle travel along the plasma membrane of a neuron or muscle fiber due to the presence of specific voltage-gated channels TISSUE REPAIR: RESTORING HOMEOSTASIS - Tissue repair is the process that replaces worn out, damaged, or dead cells ▪ Epithelial cells are replaced by the division of stem cells or undifferentiated cells  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 ▪ Not all connective tissue cells have the SUPPLEMENTAL NOTES ability to repair ▪ Muscle cells can perform limited repair Epithelial Tissue: ▪ Some nervous cells can perform limited Structural and Functional Relationships repair, others cannot - Cell connections - Fibrosis is the formation of scar tissue o Tight junctions bind adjacent cells together and form a AGING AND TISSUES permeability barrier o Desmosomes mechanically bind Aging cells together - Younger bodies generally experience: o Hemidesmosomes mechanically o A better nutritional state bind cells to the basement o A better blood supply to tissues membrane o A faster metabolic rate o Gap junctions allow intercellular - Aging slows the process of tissue repair communication - Aging also results in stiffening and loss of elasticity in tissues Homeostatic Imbalances - Disorders of epithelial tissues tend to be specific to individual organs, such as ulcers in the stomach - Disorders of connective tissues tend to be autoimmune in nature, such as lupus - Disorders of muscular and nervous tissues will be discussed in later chapters Epithelial Tissue Functions 1. Protecting underlying structures - Example: outer layer of skin and oral mucosa 2. Acting as barrier - Example: outer layer of skin 3. Permitting the passage of substances - Example: epithelium in the lungs 4. Secreting substances - Example: mucous glands and sweat glands 5. Absorbing substances - Example: epithelial cells of the intestine  HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 Epithelial Tissue Classification - Epithelia are classified according to the number of cell layers and the shape of the cells o Cell layers ▪ Simple epithelium has one layer of cells ▪ Stratified epithelium has more than one cell layer ▪ Pseudostratified epithelium has one layer, but appears to have two or more layers ▪ Transitional epithelium is stratified epithelium that can be greatly stretched o Cell shape ▪ Squamous are flat and thin ▪ Cuboidal are cubelike ▪ Columnar are tall and thin HUMAN ANATOMY AND PHYSIOLOGY 1 INTRODUCTION TO HUMAN BODY RESPIRATORY THERAPY A.Y. 2024-2025 Epithelial Tissue Glands - Exocrine Glands and Secretion Types o Merocrine – no loss of cellular material (Ex. Sweat glands) o Apocrine – part of the cell pinches off (Ex. Mammary glands) o Holocrine – entire cell is shed (Ex. Sebaceous glands)