Histology Flashcards
Give 3 descriptors of skeletal muscle cells
Striated, unbranched and multinucleate
Describe the length and width of skeletal muscle cells
Fibres span the whole length of the muscle (so are very long) but are a normal width.
Where are the nuclei in muscle cells?
At the peripheries as pushed by all the proteins
Type 1 fibres also known as ___1____ appear darkest due to ___2___ Type 2A fibres are relatively ___3____ Type 2B fibres also known as ___4_____ contain much less _____5______ so appear ___6_____
1) red fibres
2) abundant mitochondria and myoglobin
3) uncommon
4) white fibres
5) mitochondria and myoglobin
6) lighter
Muscle fibres are grouped into bundles called?
Fascicles
Define the perimysium, the epimysium and the endomysium
Perimysium- connective tissue around the fascicle
Endomysium- connective tissue surrounding individual fibres
Epimysium- connective tissue around the whole muscle
Each muscle fibre contains many what? What do these contain?
Many myofibrils that consist of many sarcomeres placed end to end
4 characteristics of cartilage?
Semi rigid, deformable, permeable and avascular
What are cell found in cartilage called?
Chondrocytes (chondroblasts when immature)
Where are chondrocytes found?
Extracellular matrix termed a lacuna
What do chondrocytes do?
They secrete and maintain the ECM around them
What is the extracellular matrix of hyaline cartilage made up of?
75% water, 25% organic material
Of the organic material in hyaline cartilage, what is this made up of?
60% is type 2 collagen which is a less common finer form of collagen that forms a 3D meshwork as opposed to linear bundles. 40% is proteoglycan aggregates.
What are the 3 types of cartilage?
Hyaline, elastic and fibrocartilage
Describe hyaline cartilage?
blue, white, translucent, most common, found on articulation surfaces of bones
Describe elastic cartilage?
yellow in colour, elastic fibres add flexibility, found in the ear
Describe fibrocartilage?
white, hybrid between tendon and hyaline, found in the pubic symphysis.
Functions of bone?
Provides support, levers for movement, protection, calcium store and haemopoiesis,
Three characteristics of bone?
Rigid
Not Permeable
Cells within the bone must be nourished by blood vessels that pervade the tissue.
By early 20s usually only axial and limb girdle skeleton is involved in __________
blood production
What are the two types of bone?
Dense cortical and spongy trabecular, cortical bone is on the outside
Main difference between trabecular and cortical bone?
Presence of spaces adjacent to trabecular bone
Why is bone strong?
It is backed up by layers of collagen fibres that overlap at 90
Bone is living tissue penetrated by____1_____ It contains living cells called ___2______
1) small canals for blood vessels and nerves
2) osteocytes
What are cement lines?
Visible lines surrounding osteon
What contains blood vessels?
Contains the blood vessels in bones
What is an osteon?
Cylindrical structures containing mineral matrix and living osteocytes connected by cannaliculi which transports blood
Trabecular bone often lacks _______ as osteocytes can survive from contact with marrow spaces
haversion canals
What are osteoprogenitors?
pool of reserve for osteoblasts
What are osteoblasts?
bone forming cells
What are osteocytes?
Bone cells within the bone matrix
What are osteoclasts?
cells that break down bone
Bone is constantly being remodelled. A number of __1____ congregate to drill a tunnel in the bone ___2____ grows bringing ___3____ which begin laying down lamellar bone
1) osteoclasts
2) blood vessel
3) osteoblasts
Describe woven bone
This occurs during development or following injury. Collagen fibres are laid down in a haphazard fashion. It will later be remodelled into lamellar bone.
