Adipose Tissue and Cartilage Flashcards
What is adipose tissue?
Loose connective tissue, supported by reticular fibers
Adipocytes are
Characteristic cells of adipose tissue (fat). Derived from mesenchyme
Functions of adipose tissue
-Store energy
-Cushioning the body and organs
-Thermoregulation by insulation and heat production
Fat cells are specialized for
Energy storage of lipid droplets of triglycerides
Where is subcutaneous fat found?
Under the skin for thermoregulation
Where is visceral fat found?
-Cushioning organs such as heart, gonads, kidneys, intestines
-Bone marrow
-Between muscles
-Breast tissue
Locations of white adipose tissue
- Face
-Periarticular, pericardial, intramuscular, bone marrow
-Subcutaneous
Locations of brown adipose tissue
-Cervical
-Supraclavicular
-Axillary
-Paravertebral
Characteristics of white adipose tissue
-Single huge droplet
-Fewer mitochondria
-storages energy
-Subcutaneous and visceral locations
-Fewer capillaries
-Fibroblast and microphages
Characteristics of brown adipose tissue
-Many smaller lipid droplets
-More mitochondria
-Kidneys, adrenal glands, and a few other places
-Produces heat
-More capillaries
-Fibroblast and macrophages
White adipocytes store lipids derived from three sources
-Dietary fats (triglycerides and cholesterol) packaged as chylomicrons
-Triglycerides produced in the liver and circulating as VLDL
-Fatty Acids produced locally by breakdown of the dietary fats and triglycerides
How are lipids released from adipocytes
-By enzyme lipase activated by the hormone norepinephrine from adrenal gland
Brown adipose
-Localized to kidneys, adrenal glands, and other places
-Newborns have 2-5% body weight in brown fat
-Brown because of the many mitochondria and small lipid droplets
-Produce heat by nonshivering thermogenesis
-Norepinephrine activates breakdown of lipids to fatty acids and glycerol
Three lipids
-Triglycerides
-Cholesterols
-Phospholipids
-All transported by lipoproteins
Lipoproteins
Transport fat molecules in water, blood plasma, and other extracellular fluids and taken by endocytosis
Chylomicrons (ULDL)
-Transport dietary lipids from the intestine to other locations in the body
-ULDL are one of the five lipoproteins that enable fats and cholesterol to move within the bloodstream
Atherosclerosis
Elevated levels of cholesterol in blood which increases the risk of heart attack, stroke, and peripheral artery disease
Plaque
Build up of fats, cholesterol, and other substances in and on the artery walls (Astherosclerosis)
Leptin hormone
Produced by white adipocytes, helps inhibit hunger which diminishes fat storage
Obesity
-Excessive adipose tissue accumulation. Fat increases in cells, fat cells don’t increase in number
-Decreased sensitivity to leptin resulting in inability to feel full
General features of cartilage
-Large amount of ECM with GAG and proteoglycans
-Cartilage at joints has a smooth and lubricated surface
Cartilage guides the development of
many bones, specifically endochondral bones
Chondrocytes
only type of cell in the ECM located in lacunae
Perichondrium
Dense, vascularized connective tissue that covers cartilage except at the joints
Glycosaminoglycans (molecules in ECM)
-Support and bind cells together
-Mucopolysaccharides and proteoglycans
Glycoproteins
A glycan linked to a protein. Molecules such as collagen, mucins, antibodies, and certain hormones
Hyaline cartilage is found in
-Cartilages in nose
-Articular cartilage of a joint
-Costal cartilage
-Cartilage of joint
-larynx
-trachea
Elastic cartilage is found in
-External ear
Fibrocartilage is found in
-Pubic symphysis
-Cartilage of intervertebral discs
-Meniscus in knee joint
Hyaline cartilage
-Homogenous and collagen
-Chondrocytes and chondroblast
-Perichondrium
-Respiratory tract, articular ends and plates of long bones, fetal skeleton
-Provides smooth, low-friction surfaces in joints and structural support for respiratory tract
Elastic cartilage
-Collagen and elastic fibers
-Chondrocytes and chondroblast
-Perichondrium
-External ear, auditory tube, epiglottis and other laryngeal cartilages
-Provides flexible shape and support of soft tissues
Fibrocartilage
-Collagen and large areas of dense connective tissue
- Chondrocytes and fibroblast
-NO perichondrium
-Intervertebral discs, pubic symphysis, meniscus, and certain other joints, insertion of tendons
-Provides cushioning, tensile strength, and resistance to tearing and compression
Most abundant type of cartilage, homogenous composition, semilucent
Hyaline Cartilage
What cartilage allows low friction joint motion, support respiratory passages, connects ribs to sternum and controls long bone growth at epiphyseal plates
Hyaline cartilage
T/F: Hyaline cartilage is avascular
True. Chondrocytes reproduce under low oxygen and glucose is metabolized anaerobically
Somatotropin
Growth hormone which regulates cartilage growth
Osteoarthritis
Results from dislodged fragments of joint cartilage that trigger release of substances that causes inflammation and pain
Similar to hyaline cartilage but with elastic fibers
Elastic cartilage
Mixture of hyaline cartilage and dense connective tissue
Fibrocartilage
Cartilage form from
Embryonic mesenchyme by chondrogenesis
In developing bones, cartilage growth can be
-Interstitial (within the cartilage) by mitosis of chondrocytes
-Appositional by production of new chondroblasts from the perichondrium
Cartilage does not repair well due to
Lack of vascularity
