Week 2 - tissue Flashcards
Exocrine Gland
- release substance through ducts onto an epithelial surface or directly into a body cavity.
- normally at or near surface
- sweat glands in the skin, salivary glands in the mouth, and digestive glands in the gastrointestinal tract.
primarily simple cuboidal and columnar epithelial cells
Endocrine Gland
- release substances (hormones) directly into interstitial fluid which defuses into the blood. They are ductless and typically located deep within the body
-thyroid gland, adrenal glands, and pituitary gland, islets of langerhans (pancreas)
primarily simple cuboidal and columnar epithelial cells
Define Merocrine Secretion
Merocrine secretion is the most common. Cells release products via exocytosis of vesicles. These include sweat glands, salivary glands, lacrimal glands, gastric glands, and islets of langerhans in the pancreas.
State the three types of secretion
Merocrine: Most common. Exocytosis of vessels. Sweat glands / gastric glands
Apocrine: involves loss of cytoplasm. Occurs in mammary glands
Holocrine: Entire cell bursts. Occurs in sebaceous glands
Define Apocrine Secretion
Apocrine secretion is a secretion which involves the loss of apical cytoplasm. Secretory product accumulates at the apical surface and is pinched off with a portion of the cell membrane and cytoplasm.
Apocrine secretion occurs in the mammary glands
Define Holocrine Secretion
In holocrine secretion the entire cell is packed with secretory products which are released when the cell bursts. This destroys the entire gland and stems cells must replace the gland. Have stem cells in basal layer that are constantly dividing.
occurs in sebaceous glands
What do goblet cells do? Where are they found?
Goblet cells are specialized epithelial cells which secrete mucus. They are primarily found in the respiratory and digestive tracts.
Name some functions of connective tissue
Connective tissue is the most diverse type of tissue and aids in structural support, protection, energy storage (adipose tissue), fluid transport (blood), and immune response.
Connective tissue will never line a space. Always has overlying layer of epithelium.
It is highly vasculated (except cartilage).
Name Two components of Connective Tissues
Connective tissues are made of cells (fibroblasts, adipocytes, macrophages…) and an extracellular matrix. It provides structural support, and anchors cells in placer. The matrix is composed of a ground substance and fibers. The cells are not in contact
List three main categories of connective tissue and subcategories
-
Connective Tissue proper
- loose connective tissue: areolar, reticular, adipose
- dense connective tissue: dense regular, dense irregular, elastic -
Supporting connective tissue
- cartilage: hyaline cartilage, fibrocartilage, elastic cartilage
- bone -
Fluid connective tissue
- blood
- lymph
Describe Two componente of extracellular matrix of connective tissues
Ground Substance
A gel-like substance that is primarily composed of water glycosaminoglycans, proteoglycans, and glycoproteins. Fills the space between fibers.
Fibers
Structural proteins which provide support and elasticity. These proteins include collagen fibers (strong and do not stretch), reticular fibers (network of branching collagen) and elastic fibers (made of elastin look like worms).
Describe the three types of connective tissue fibers.
Collagen: Collagen fibers are the most abundant and strongest fibers in connective tissue they do not stretch. They are composed of collagen protein.
Collagen fibers provide tensile strength, resistance to stretching, and support to tissues
Reticular: Reticular fibers are fine/thin, branching fibers that form a delicate network within connective tissue. They are composed of collagen proteins and glycoproteins. Reticular fibers provide a supportive framework for organs such as the liver, and spleen. They also support the basement membrane of epithelial tissues (reticular lamina below basal lamina basement membrane) and blood vessels.
Elastic: Elastic fibers are thinner than collagen fibers and are composed primarily of elastin protein. Elastic fibers provide elasticity and resilience to tissues. They are important in tissues that undergo repeated stretching and recoiling, such as skin, lungs, blood vessels, and elastic ligaments.
Define Mesenchymal cells
Mesenchymal cells are undifferentiated, multipotent stem cells found in connective tissue. Play a key role in tissue repair and regeneration.
can differentiate into a variety of cell types, including osteoblasts (bone cells), chondrocytes (cartilage cells), fibroblasts (primary connective tissue), myocytes (muscle cells) and adipocytes (fat cells which give rise to marrow adipose tissue).
Define Fibroblasts
The primary cell type in some connective tissue - conective tissue proper (minus adipose). Produces collagen fibers (type I, III), elastic fibers, and extracellular matrix.
collagen type I -> collagen -> most abundant
collagen type II -> most common collagen in cartilage
collagen type III -> reticular fiber
Chondroblasts are the cells responsible for producing the fibers and matrix of cartilage, while fibroblasts are responsible for producing the fibers and matrix of connective tissue proper chondroblasts: Found in cartilage. Primarily produce type II collagen and proteoglycans, elastic fibers (elastic cartilage). Once they become embedded in the matrix they mature into chondrocytes and maintain the matrix. Fibroblasts: Found in connective tissue proper. Produce and maintain the extracellular matrix of connective tissues. Primarily produce type I collagen, type III collagen (reticular fibers), elastic fibers (elastin and fibrillin), and other extracellular matrix components.
Define Macrophages
Large phagocytic cells that wander through connective tissue. They engulf and destroy bacteria, foreign particles, or dead/dying cells.
Define Leukocytes
Leukocytes are various types of white blood cells which travel to connective tissue via the bloodstream where they spend most of their time. Neutrophils attack bacteria. Lymphocytes (B cells, T cells) react against foreign substances, toxins, and other foreign agents.
Define Fibrocytes
Fibrocytes are inactive, mature fibroblasts that maintain (do not produce it) the ECM of connective tissue. They maintain the structural components of the ECM.
Define adipocytes
Adipocytes are specialized cells found in adipose tissue, commonly known as fat cells. Their primary function is to store energy in the form of fat (lipids), which can be used by the body as a source of energy during times of need. Adipocytes also play roles in thermal insulation, cushioning organs, and secreting hormones that regulate metabolism. They vary in size and shape depending on the amount of fat they store.
deep to skin, pad eyes and kidney
Areolar connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Types: Fibroblasts, Mast cells, Plasma cells, Adipocytes. Leukocytes (white blood cells)
Fiber Types: Collagen, elastic, reticular fibers
Fiber arrangement: Loose, random network. Mesh like
Functions: Supports and binds tissues; holds organs in place; provides elasticity
Locations: hypodermis, subserous fascia, endoneurium, endomysium, lamina propria (mucus membrane)
composed of fibroblasts and many other cell types with loosely intertwined collagen, elasalstic, and reticular fibers. semi-fluid ground substance
strength, elasticity, support
Adipose connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: primarily adipocytes, some fibroblasts, macrophages
Fiber Type: Collagen, reticular. Scarce
Fiber arrangement: Sparse arrangement
Function: Energy storage, thermal insulation, cushioning (supports and protects organs)
Location: Subcutaneous layer of skin, around some organs (pad eyes, and kidney),
large triglyceride
Reticular connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell types: Reticular cells (type of fibroblast), macrophages, lymphocytes
fiber types: Reticular fibers
fiber arrangement: network of thin fibers, branching and mesh-like.
functions: Forms a supporting framework of organs and forms net to capture microbes and worn-out blood cells
locations: Liver, kidney, spleen, lymph nodes, bone marrow
cells spaced between fine interlacing reticular fibers
Dense Regular connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: Fibroblasts
Fiber Type: collagen fibers
fiber arrangement: parallel arrangement
function: provides strong attachment and tensile strength. Stabilizes bones
locations: Tendons and ligaments
regularly arranged parallel bundles of collagen fibers -> looks very similar to smooth muscle
Dense irregular connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: Fibroblasts
Fiber Type: collagen, elastic
fiber arrangement: irregular / wavy
function: provides multi-directional strength
location: reticular layer of dermis, periosteum, perichondrim, perimysium, epimysium, perineurium, epineurium, deep fascia, fibrous synovial joint capsules.
numerous fibers (in multiple directions) with many fibroblasts
Elastic connective tissue
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: fibroblasts
fiber type: elastic fibers, collagen fibers,
fiber arrangement: wavy dense
function: flexible support
locations: deep to transitional epithelium of bladder, walls of large blood vessels, walls of bronchioles in lungs,
more elastic fibers than collagen -> appears wavy
Blood
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
cell type: The main types of cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
fiber: soluble fibrinogen proteins
Function: Transport nutrient, immunity
Location: All over RBC, WBC, platelets
Hyaline Cartilage
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: chondrocyte, which are embedded in lacunae. Normally in clusters of three to four cells.
Fiber type: Type II collagen fibers embedded in gel-like matrix. Normally not visible
fiber arrangement: The collagen fibers in hyaline cartilage are arranged in a fine, homogeneous network throughout the matrix.
Function: Reduces friction and absorbs shock at joints, provides flexibility and support
Locations: epiphyseal plate, articulating cartilage of synovial joints, costal cartilage, cartilage rings of trachea and bronchi
Elastic Cartilage
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: chondrocyte, which are embedded in lacunae
Fiber Type: elastic fibers in addition to collagen fibers.
Fiber arrangement: branching network embedded within matrix
Function: Provide strength and elasticity, help maintain shape of structures
Location: Outer ear, epiglottis, auditory canal
Fibrocartilage
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: chondrocyte, which are embedded in lacunae
Fiber type: dense network of collagen fibers, primarily type I collagen
Fiber Arrangement: The collagen fibers in fibrocartilage are arranged in thick bundles or layers within the matrix.
Function: Resists compression, bone-bone impact
location: menisci (knees, TMJ), annulus fibrosus, symphysis between pubic bones, glenoid labrum, acetabular labrum
not covered by perichondrium
Bone
Cell Type
Fiber type
Fiber arrangement
Functions
Locations
Cell Type: osteoblasts, osteocytes, and osteoclasts. Osteoblasts are responsible for bone formation, osteocytes maintain bone tissue, and osteoclasts are involved in bone resorption.
Fiber type: collagen fibers, primarily type I collagen
Fiber Arrangement: Collagen fibers are arranged in a parallel manner within the bone matrix, providing structural support and resilience
Functions: Support, protection and storage, provides leverage for movement
Locations: All over
What are thre three types of fascia, where are they found, connective tissues are found within each?
superficial
Description: Layer of connective tissue located directly beneath the skin - subcutaneous layer. Provides structural support and protection to underlying structures, thermal regulation, nutrient storage, cushioning and padding
Location: Between skin and underlying organs (hypodermis).
Tissue Type: Areolar tissue and adipose tissue
Deep
Description: Forms a strong fibrous internal framework
Location: that surrounds and separates muscles, bones, nerves, and blood vessels throughout the body. Bound to capsules, tendons, and ligaments,
Tissue Type: Dense connective tissue.
Subserous
Description: It also helps anchor the serous membranes to the underlying structures.
Location: between serous membranes and deep fascia
Tissue type: areolar
Describe characteristics of bone, functions, and locations
osseous tissue
Structure: Consists of osteocytes within lacunae, fibers (primarily collagen), and enmeshed calcium phosphate crystals. Most compact bone is arranged in cylinders surrounding a central canal. Blood vessels run through the canal. canaliculi radiate from each lacuna allowing osteocyte communication.
Function:
- Bones provide structural support and protect vital organs.
- Bones serve as attachment points for muscles allowing for movement.
- Bones store calcium and phosphate - helping maintain homeostasis.
- Bone marrow produces blood cells
- Bone tissue stores some lipids acting as an energy reserve.
Features:
- extensively vasculated
- very strong
- has high oxygen demands
- extensive repair capacities
Location:
Everywhere
Describe cell shape, striations, nucleus count, ability to repair, involuntary, locations, and functions of skeletal, cardiac, and smooth muscle
State two general types of cells in nervous tissue and functions
Neurons: Transmit electrical signals, consist of dendrites, cell body, and axons. Bad at regenerating.
can be anaxonic, unipolar, or multipolar, depending on number of projections (axons / dendrites)
Neuroglia / glial cells: support, protect, insulate and supply nutrients to nuerons
Describe mucous membranes
- Line body cavities that open to the outside
- allow absorption, secretion, and provide protection,
- epithelial layer secretes mucus
- the epithelium rests on an areolar tissue layer, the lamina propria
The lamina propria is a layer of loose connective tissue areolar that lies beneath the basement membrane and the epithelial layer. It is part of the mucous membranes found in various organs, such as the respiratory tract, gastrointestinal tract, and genitourinary tract. The lamina propria contains:
