Histology Flashcards
Skeletal muscles are
striated, unbranched and multinucleate
What is the name of the connective tissue that surrounds the muscle
epimysium
What is the name of the connective tissue around a single fascile
Perimysium
What is the name of he connective tissue around a single muscle fibre?
endomysium
What are sarcomeres
The unit of contraction of the muscle cell ( the smallest contractile elements the striated muscle cell)
Why is dark meat dark?
it has more muscle
The fibres in a motor unit are scattered in the muscle ( not bunched together) and are all of the same fibre type. T/F
T
Describe cartilage
Semi-regid and deformable
Permeable
Avascular
Cells nourished by diffusion through the extracellular matrix
Describe BONE
rigid
non permeable
Cells within the bone must be nourished by blood vessels that pervade the tissue
What are the cells found within cartilage called
Chondrocytes (chondroblasts when immature)
Where do the chondrocytes live
within a space in the extravascular matrix termed the lacuna - cartilage
What is the most common form of cartilage
ECM
What is the mot common cause of cartilage found in connective tissues
Type 1
Hyaline cartilage
Blue-white in colour and translucent
Most common form of cartilage
Elastic cartilage
Light yellow in colour
quite flexible
Fibrocartilage
Hybrid between tendon and byline cartilage
Bands of densely packed type 1 cartilage interleaved with rows of chondrocytes, surrounded by small amounts of cartilaginous ECM
Tens to appear white
Where is hyaline cartilage found?
Articular surfaces tracheal rings Costal cartilage Epiphyseal growth plates Precursor in fetes to many bones
What are the functions of bone?
To provide- support levers protection of organs calcium store (95% of total calcium) Haemopoiesis
In utero where is blood produced
liver and spleen (begins in bone marrow well before birth)
An outer shell of dense ___ bone makes up the shaft (____)
cortical bone
diaphysis
____ or _____ bone occupies the ends of the bone ( the ____)
Cancellous
trabecular
epiphyses
what bone looks like an aero bar?
cancellous
What is the main difference between the bone cells and matrix in compact and trabecular bone
the presence of spaces ( marrow cavities) adjacent to trabecular bone
What does lamella mean?
Made up of layers
What are the living cells contained within bone called
osteocytes
What are the lines that are visible surrounding the osteon called?
Cement lines ( only present in osteons that are formed during remodelling)
What does trabecular bone lack and why?
lack Haversian canals
( because the struts are thin, the osteocytes can survive from contact with the marrow spaces
What are osteoprogenitor cells
Located on bone surfaces, for example under the periosteum, these cells serve as a pool for reserve osteoblasts
What are osteoblasts
bone forming cells found on the surface of developing bone. They have plentiful RER and prominent mitochondria
What are osteocytes
a bone trapped within a bone matrix
What are osteoclasts?
large multinucleate cells. They are found on the surface of bone and are responsible for bone reabsoption
Describe the process of remodelling?
A number of osteoclasts will congregate and begin to “drill” into the bone, forming a tunnel. A blood vessel will grow into the tunnel bring with it osteoblasts which line the tunnel and beginning down new lamellar bone. This process continues until only the space of Haversian canal remains
What is the BMU
Basic multicellular unit
- the collection of osteoclasts and osteoblasts that participate in remodelling
What do the osteoblasts secrete?
Collagen, glycosaminoglycans (GAGs), proteoglycans and other organic components of the matrix (collectively termed osteoid)
