Week 3 Flashcards
What are the two main types of epithelial tissue?
- Covering and Lining epithelium
- Glandular epithelium
What is the function of covering and lining epithelium?
It forms the outer layer of the skin, lines body cavities, and covers the walls and organs within the body.
What are the key characteristics of epithelial tissue?
- Polarity (Apical and Basal Surfaces)
- Specialized Contacts (tight junctions, desmosomes)
- Supported by connective tissue (basement membrane)
- Avascular but innervated
- Strong regenerative ability
What is simple epithelium?
A single layer of cells, found in areas where absorption, secretion, and filtration occur (e.g., alveoli in lungs, kidney glomeruli).
What is stratified epithelium and where is it found?
Stratified epithelium consists of two or more layers of cells, found in areas exposed to mechanical stress (e.g., skin).
What is pseudostratified epithelium?
Pseudostratified epithelium appears to be stratified but is actually a single layer of cells, found in the respiratory tract.
What are the different cell shapes in epithelial tissue and their functions?
- Squamous: Flat and thin, for diffusion and filtration (e.g., blood vessels).
- Cuboidal: Cube-shaped, for secretion and absorption (e.g., kidney tubules).
- Columnar: Tall and rectangular, for secretion and absorption (e.g., digestive tract).
- Transitional: Cells change shape, for stretching (e.g., urinary bladder).
What are endocrine glands?
Endocrine glands are ductless, secrete hormones into the blood or lymph to target organs (e.g., pituitary, thyroid).
What are exocrine glands and how are they classified?
Exocrine glands secrete products onto epithelial surfaces via ducts. They are classified as:
1. Unicellular (e.g., goblet cells)
2. Multicellular (e.g., sweat glands, salivary glands
How are multicellular exocrine glands structurally classified?
- Based on duct structure:
Simple (unbranched ducts)
Compound (branched ducts) - Based on secretory units:
Tubular
Alveolar
Tubuloalveolar
What is connective tissue and its main function?
Connective tissue is the most prevalent tissue in the body and plays a critical role in supporting and connecting other tissues and organs
What are the four main classes of connective tissue?
- Connective Tissue Proper
- Cartilage
- Bone
- Blood
What are the functions of connective tissue?
- Binding and supporting
- Protecting
- Insulating
- Storing reserve fuel
- Transporting substances
What are the structural elements of connective tissue?
- Ground substance
- Fibres
- Specific cell types (e.g. -blast, -cyte)
What is the function of collagen fibres in connective tissue?
Collagen fibres provide high tensile strength and toughness
What is the function of elastic fibres in connective tissue?
Elastic fibres stretch and recoil like rubber bands, providing flexibility
What are reticular fibres and their function?
Reticular fibres are short, fine collagenous fibres that form delicate networks to support cells.
What is the difference between -blast and -cyte cells in connective tissue?
-blast cells are immature and actively proliferating, while -cyte cells are mature and maintain the health of the matrix
What is the function of white blood cells in connective tissue?
White blood cells (e.g. neutrophils, lymphocytes) are involved in immune responses.
What are the subtypes of connective tissue proper?
- Loose connective tissue
- Dense connective tissue
What is the function of areolar connective tissue?
Areolar connective tissue supports and binds tissues, defends against infection, holds body fluids, and stores nutrients.
What is the function of adipose tissue?
Adipose tissue stores energy (lipids), cushions, and insulates the body.
What is the function of dense regular connective tissue?
Dense regular connective tissue provides strength and structure, found in tendons, ligaments, and fascia.
What is the function of hyaline cartilage?
Hyaline cartilage provides strong support and shock absorption, found in joints.
What is the function of bone tissue?
Bone tissue provides structural support, protects vital organs, stores minerals, and synthesizes blood cells in the bone marrow.
What is the function of blood?
Delivers necessary substances, such as nutrients and oxygen, to the cells and transports metabolic waste products away from those same cells
Appearance: red and white blood cells surrounded by a non living fluid (plasma)
What is the function of muscle tissue?
Muscle tissue is specialized for movement and converts chemical energy (ATP) into mechanical energy to generate motion.
What are the three main types of muscle tissue?
- Skeletal Muscle
- Smooth Muscle
- Cardiac Muscle
What is the location and function of skeletal muscle?
Skeletal muscle is attached to bones and enables voluntary movement (e.g., walking, lifting). It is controlled voluntarily.
What is the structure of skeletal muscle?
Skeletal muscle consists of long, cylindrical, multinucleate cells with a striated appearance.
What is the location and function of smooth muscle?
Smooth muscle is found in the walls of hollow organs (e.g., stomach, intestines, blood vessels) and helps move substances (e.g., food, blood) through these organs. It is controlled involuntarily.
What is the structure of smooth muscle?
Smooth muscle consists of spindle-shaped cells with central nuclei, no striations, and cells arranged closely together.
What is the location and function of cardiac muscle?
Cardiac muscle is found only in the walls of the heart, where it propels blood through the heart and into blood vessels. It is controlled involuntarily.
What is nervous tissue and what is its primary function?
Nervous tissue is the primary component of the nervous system (brain, spinal cord and nerves) and is responsible for regulating and controlling body functions.
What are the two main types of cells in nervous tissue?
Neurons (nerve cells) and glial cells (supporting cells)
What are the functions of the nervous tissue?
- Transmit electrical impulses
- Respond to stimuli
- Control muscles and coordinate movement
What is the structure of a neuron?
A neuron consists of a cell body (with nucleus), dendrites (carry signals toward the cell body), and an axon (carries signals away from the cell body).
What is the function of dendrites in a neuron?
Dendrites carry electrical signals toward the cell body of the neuron.
What are glial cells and their functions?
Glial cells support and nourish neurons, protect them, maintain electrolyte balance, repair the nervous system, and form myelin sheaths. Types include astrocytes, oligodendrocytes, microglia, and Schwann cells.
What role do astrocytes and oligodendrocytes (Schwann cells) play in the nervous system?
Astrocytes form the blood-brain barrier, while oligodendrocytes (in the CNS) and Schwann cells (in the PNS) form myelin sheaths around axons, aiding in faster signal transmission.
What are the two processes involved in tissue healing?
Regeneration (complete restoration of tissue) and repair (scar formation without restoring full tissue structure).
How does tissue regenerative capacity vary across different tissues?
Well: Epithelial tissue, bone, blood-forming tissue.
Moderate: Smooth muscle, dense regular connective tissue.
Weak: Skeletal muscle, cartilage.
No functional regeneration: Nervous tissue, cardiac muscle.
What is the role of stem cells in tissue regeneration?
Stem cells divide repeatedly and can differentiate into various cell types, helping in tissue growth and repair.
What two properties make stem cells unique for tissue healing?
- They divide continuously to produce new cells.
- They can differentiate into various cell types to replace damaged tissues.
Why is vascularization important for tissue repair and regeneration?
Blood vessels supply necessary nutrients and remove waste, which is crucial for the regeneration and repair of tissues.
