Class Notes (922,826)
CA (542,992)
UTSC (32,983)
BIOC21H3 (35)
Lecture 6

BIOC21 Lecture 6 Notes

7 Pages
46 Views

Department
Biological Sciences
Course Code
BIOC21H3
Professor
Stefan Rusyniak

This preview shows pages 1-2. Sign up to view the full 7 pages of the document.
BIOC21 - Lecture 6 - Muscle
1
- 3rd basic histological tissue type: Muscle
- fairly straightforward unlike the others, there's not a lot of subdivisions
- only have to worry about three types: smooth, skeletal, and cardiac
- how do they differ, and how is muscle generally like?
2
- smallest component: myofilament (protein structure within a muscle cell:
actin or myosin)
- tend to be organized into larger structures: myofibril (bundle of
myofilaments)
- myocyte: actual cell that contains the myofibrils composed of myofilaments
- when we talk about muscle cells, we refer to them as fibres, which confuses
most
- the cells themselves in most cases are very large and shouldn't be
called cells because they are aggregations of multiple cells (ie multiple
myoblasts fusing together to form what is known as a syncytium (bag of
cells); a larger structure composed of many cells fused together which is
why we refer to them as fibres; in skeletal muscle, you can have a single
cell spanning the entire length of the entire muscle which is very large for a
cell which is why we refer to them as fibres)
- older terms:
- sarcosome: muscle cell; also referred to as the mitochondria of a cell
(can be confusing, we won't be using this term!)
- 'sarco' = muscle
- sarcoplasmic reticulum is the only one from these terms the prof will
use because the ER of muscle tissue is very specialized, because it's a place
to store calcium which is important for muscle contraction; used as a
calcium storage vesicle
3
www.notesolution.com
- 'pearls on a string' type of arrangement: actin filaments
- we talk about actin and myosin, but there are more specific accessory
proteins involved as well
- when you want to initiate muscle contraction, you have to move tropomyosin
out of the way
- actin is typically referred to as a thin filament; myosin referred to as a thick
filament
- actin is two thin strings
- myosin is 200-300 filaments
- sarcomere is the functional unit of a muscle fiber, it's where contraction
begins
- myofibril bundled together to make a fascicle and the fascicles are bundled
together to make up a muscle which will be attached to bone by tendons
4
- major cell type: myocyte aka muscle fibre
- myoblast: immature form of muscle cell , not filled in with protein, will fuse
with others to produce a muscle fiber or differentiate into a muscle cell itself
- fibroblasts are also present because the muscle needs to be connected to the
bones somehow and they will be found here
- transmitting contraction to tissue, done by the tissue which wraps the
muscle as well as the tendon
- CT: collagen fibres, tendons: thick bundles of collagen, embedded on
one end by bone (recall Sharpey's fibres); continuous fibre that goes from
tissue to fibre
- CT that surrounds the muscle is called fascia
- length of tendon will stay the same, they do not stretch
- lots of capillaries in the fascia connect the BVs, but also serves as a
means of attachment between the muscle and tissue
- the attachment is provided by protein complexes (composed of
proteins called dystrophins; think muscular dystrophy: muscle
www.notesolution.com

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
BIOC21 - Lecture 6 - Muscle 1 - 3rd basic histological tissue type: Muscle - fairly straightforward unlike the others, theres not a lot of subdivisions - only have to worry about three types: smooth, skeletal, and cardiac - how do they differ, and how is muscle generally like? 2 - smallest component: myofilament (protein structure within a muscle cell: actin or myosin) - tend to be organized into larger structures: myofibril (bundle of myofilaments) - myocyte: actual cell that contains the myofibrils composed of myofilaments - when we talk about muscle cells, we refer to them as fibres, which confuses most - the cells themselves in most cases are very large and shouldnt be called cells because they are aggregations of multiple cells (ie multiple myoblasts fusing together to form what is known as a syncytium (bag of cells); a larger structure composed of many cells fused together which is why we refer to them as fibres; in skeletal muscle, you can have a single cell spanning the entire length of the entire muscle which is very large for a cell which is why we refer to them as fibres) - older terms: - sarcosome: muscle cell; also referred to as the mitochondria of a cell (can be confusing, we wont be using this term!) - sarco = muscle - sarcoplasmic reticulum is the only one from these terms the prof will use because the ER of muscle tissue is very specialized, because its a place to store calcium which is important for muscle contraction; used as a calcium storage vesicle 3 www.notesolution.com
More Less
Unlock Document


Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit