Quiz 2 Flashcards
What is the strongest type of cartilage?
Fibrocartilage
What is the weakest type of cartilage?
Hyaline cartilage
Fibrocartilage contains what type of collagen fibers?
Type I and II
Which cartilage lacks a perichondrium?
Fibrocartilage
Where would you likely find fibrocartilage?
Sites subject to pressure and stretch; menisci of knee, intervertebral discs, pubic symphysis
Which cartilage contains elastic fibers?
Elastic cartilage
Where would you find elastic cartilage?
external ear, epiglottis; in areas able to stand up to repeated bending and maintain shape.
Which cartilage types contain a perichondrium?
Hyaline, Elastic
The axial skeleton contains what skeletal elements?
Skull, vertebrae, ribs and sternum
Appendicular skeleton contains what skeletal elements?
Limbs and girdles (pelvic and pectoral girdle)
What are the functions of bone?
Support Protection Locomotion Hematopoiesis Mineral Homeostasis
What minerals is the bone responsible for maintaining at homeostatic levels?
Calcium, Phosphorus
Where do living cells in bone and cartilage occupy?
Lacunae
Bone is _________, and cartilage is _________. (Blood supply)
highly vascular, avascular
There is More/Less collagen found in bone than in cartilage?
more
Bone growth occurs by a process called what? And why is this needed?
Apposition, a deposition of bone on preexisting surfaces. Bone is heavily mineralized with calcium salts, and osteocytes are unable to divide due to lack of space.
Lamellae are arranged to form 2 types of architecture. What are these two types and what is the body’s composition of this?
Compact (cortical) Bone - outer layer of most bones, about 80% of bone in body
Traebecular (spongy) Bone - inside the cortical bone, about 20% of bone in body
The majority of collagen in bone is what type?
Type I
What type of collagen is in every type of cartilage?
Type II
Bone resorption is done by what cells?
Osteoclasts
Bone formation is done by what cells?
Osteoblasts
Mature bone cells are termed what?
Osteocytes
Osteoclasts attach to bone via what proteins?
Integrins
What are the areas called that osteoclasts attach to bone?
Sealing zones
What hormone regulates bone remodeling?
Parathyroid Hormone, as well as active vitamin D
What proteins are stimulated to activate osteoclasts?
RANKL (RANK ligand receptor)
List some important functions of Calcium
Second messenger for blood coaglulation, muscle contraction, nerve function
Bone calcium is available from two reservoirs, name them and identify the largest store
Exchangeable site
Stable site, where the majority of the bone is stowed
Parathyroid hormone is secreted by what?
Chief cells of the parathyroid glands
What is calcitonin and what does it do?
A blood calcium lowering hormone secreted primarily by the parafollicular cells in the thyroid gland
1, 25-dihydroxycholecalciferol is what?
A steroid hormone formed by vitamin D in skin via sun
How is 1, 25-dihydroxycholecalciferol formed?
Successive hydroxylations in the liver and kidneys
What hormoness interact to maintain calcium levels?
Parathyroid hormone and calcitonin
Defective bone matrix calcification due to vitamin D and/or calcium deficiency is what?
Rickets in children
Osteomalacia in adults - enamel hypoplasia and incomplete mineralization is commonly seen in dentition
Name some limitations to electrical signalling
Binary
Difficult to modify
Energy intensive
Microenvironment dependent
What is mainly responsible for the negative charge inside a cell membrane?
Negatively charged proteins
What are two important elements in maintaining resting membrane potential?
Ion transporters (Na/K ATPase pump) Ion Channels (K, Na, Ca, Cl)
The interior of the membrane is ________ charged
Negatively
At rest, a membrane is only permeable to what ion?
Potassium
The action potential is what?
A moving electrical event that propogates down an axon, changing the membrane potential.
The action potential is caused by what?
The sequential opening of Na and K channels in a voltage and time dependent manner, so a net flow of positive ions (Na) rush into the cell. K channels then open up and rapidly flow out of cell, leaving a negative charge in the cell once more.
What are some ion channels and functions?
Leakage - constant flow of ion along a gradient
Voltge gated - Respond to changes in membrane potential
Ligand gated - respond to ligand binding, (neurotransmitter, proteins, ions, lipids)
Physically gated - Respond to physical stimuli (mechanical, temp, light)
What are some ion transporters?
ATPase Pumps - Use ATP to move one or more substances against gradients
Ion Exchangers -
Co-Transporters -
Multiple transporter systems -
T/F: Voltage gated ion channels are time and charge dependent. Explain
True, as the membrane potential changes, there is a physical change associated with it. As membrane potential goes back to normal, channel will physically move to resting position.
What would happen if the slow leaking potassium channels in the membrane closed?
Membrane potential would go to 0. There needs to be movement of current in order to establish an electrical potential energy (Voltage)
Action potentials are initiated where in the neuron?
Axon Hillock
What is responsible for action potentials only moving unidirectional?
Refractory period of voltage gated sodium channels
What is the gap of time between action potentials?
5 - 10 milliseconds
What are the functions of cartilage?
Withstand tension and compression
Provide low friction surface at joints
Provide support to soft tissue
Provide framework for long bone osteogenesis (during development)
Cells that are main composition of cartilage are called what?
Chondrocytes
The fibrous connective tissue sheath around cartilage is called what?
perichondrium
How does cartilage receive nutrients?
Diffusion via the perichondrium