16 October 2004 I am making changes now

BUT the new notes will be merged with the old at http://biology.uta.edu/shreyas in the next week and half

This week I will discuss the importance and relevance of the integuments, and musculature. I will also highlight the interesting and important differences in muscles from the protochordates to the mammals. As usual I will leave the bulk of the work (Read your BOOK) for you.

Announcements

I will open lab tomorrow Sunday (2 Nov' 03) after 12 pm, depending on my state after tonight's Halloween bash

Open Lab - If you cannot enter the building on the weekend - contact me in advance (do not change the subject field, this forwards to my phone)

• the test will be done one week later on November 3 and 5th (there can be no further changes)

• This should interest some of you.  We will need lab assistants for the Fall of 2004, so if some of you are interested talk to Campbell or me at the end of next semester and in the summer.

• I found this opinion on line : Teaching anatomy must change

Instructions                                                                                                       

Anatomy is an exploratory endeavor. That means you have to try it your self and seek assistance when needed.

I will assert now at the start of this session, the best way to learn material for this class is to ask a lot of questions on the material you have/are examining. I believe anatomy should be learnt by feeling the structures with your hands and seeing them with your eyes; this has to be include asking questions. Ask questions regarding the notes I put online as well as what I say in class and the text in your lab book. (instructions for the practical)

You will have to make observations during the class and ask me questions, discuss among yourselves, complete your dissections, observe other groups material, reference books available in the lab...

there is a strong correlation between the lab grades and the amount of time spent examining the specimens in detail (I don't have sufficient samples to provide statistics on the same)

Please make sure you bring you bring your dissection materials to lab, a lab coat may be required. Dispose of scalpel blades in the designated bin, not with regular trash.

Dissections

We will be dissecting sharks and cats, to examine their internal anatomy; salamanders will also be examined .

We are following your lab text, read it completely, any material online is only to supplement what I feel might not have been covered in the text. First examine the external structures of your specimen, and make note of their integument, sense organs, other organs that are externally observable.

Muscular system instructions for dissection are straightforward and right out of your lab text. Read your text and re-read it while you dissect. use a fresh blade to make sure you make good dissections. Try to identify the muscles (position), blood vessels and nerves that are visible from the exterior before proceeding into the animal.

There are a lot of reference manuals in the lab, Refer them.

what I expect on the next test

• identification of muscles; names of different muscles (identify a muscle pointed to)

• terms referring to muscles and their attachments (definition / description)

• examine the bones in relation to the muscles, you should know the muscles that have their origin or insertion looking at a bone

  • I could ask you to name the muscles that originate or insert on a certain bone (ex: what are the muscles on the lateral face of the scapula)

• homology with the other animals examined in class (here we have examined muscles of the shark and cat and the salamander); you have to draw connections/ relationships beyond what the book states

• don't just focus on the dissections, also read the text, make connections between the chapters u have read , I will find questions there too (page 151 lab text: what is an anatomical rule for muscles and their innervations)

Notes

"Skeletal muscles have been named for direction of their fibers, location or position, number of subdivisions, shape, origin or insertion, action, size, and for still other features including a combination of these. Insight into the significance of a muscle's name should aid in recall of other information about the muscle." (Kent and Miller, 1997)

Read Dr. Campbell's page  Beside the dissections  and the comparisons that you ought to be making, there is not much for me to put up on this page, however watch this page for the next week and there will be pointers on what to focus on. I will put more information on homologies here - as I find them and the time to put them here

Recall the muscle segmentation observed in the Amphioxus and the Lamprey. The muscle system of the shark is also segmented (segments are homonomous), similar case in the necturus. Cephalization is prominent and increasing in specialization in all three vertebrates studied. Increasing specialization and cephalization results in decrease in segment homogeneity, however the innervations of muscles is a reliable method of determining the phylogenetic origin of the muscles (diaphragm of mammal).

Tendons join muscle to bone (shiny white), ligaments join bone to bone; these are closely packed bundles of collagen (an insoluble fibrous protein - check the definition on www.m-w.com)

Aponeuroses - tough thin sheet like expanses of mammalian tendons and ligaments (Galea aponeurotica = mammalian scalp)

Raphes - long seam like tendons (linea alba)

fascia

Origin this is usually in that bone which acts as the support or fulcrum to move or displace another bone; Insertion this is in that bone which is displaced by the contracting muscle; The origin and insertion may swap position depending on which bone is held immobilized. Thus origin and insertion are terms used to describe which bones are acted on with contraction of the muscle, and a muscle might have more than one origin or insertion

Somatic muscles - striated muscles, attached to ligaments, tendons and bones; innervated by spinal nerves; orient the body; voluntary in function

Visceral muscles - smooth muscles, in hollow organs, include cardiac muscles, innervated by autonomous nervous system

Branchiomeric muscles - homologous to the branchial/ pharyngeal muscles from fishes to mammals, striated muscles, innervated by cranial nerves

Adductor mandibulae of the first (mandibular) arch of sharks has differentiate into 2 groups of masticatory muscles in mammals - 1) as the temporalis, masseter and (the next few were not observed) external pterygoid, and 2) the internal pterygoid, tensor tympani and tensor palati. The latter two associated with the reduced (into the middle ear bones) quadrate and articular of the mammal are correspondingly small.

Temporal fossae and adductor muscles Remember observing the anapsid, diapsid and synapsid skulls. Can you draw some connection about the development of those muscles and the skull structure??

action of skeletal muscles - Campbell's page

Epaxial musculature: serves to straighten the back and in lateral flexion; metameres are distinct in amphibians (except Anura); include the intervertebrals, longissimus, spinales and iliocostales; Intervertebrals (not observed in lab) are metameric; Longissimus is the longest epaxial - capitis attaches to the skull, cervicis are in the neck, dorsi are in the trunk, + forms 3 bundles in the lumbar region of mammals. In mammals its not important for locomotion; Spinales + intervertbrals = Multifidus Spinae, maitain rigidity (erect posture in mammals) of vertebral column; Iliocostales are important for lateral undulation by virtue of their lateral position in reptiles.

If you have dissected the thoracic region of the cat and observed the forelimb lying limp, it should impress on you that the pectoral girdle no longer articulates with the head or with the vertebral column as in the fishes. What are the muscles that hold the pectoral girdle to the trunk, and what is their origin ? Lateral group of Hypaxial muscles : Serratus ventralis, Levator scapulae, Rhomboideus

Hypaxial musculature (page 186 of Hildebrand and Goslow, 2001) mostly responsible for ventral flexion of the spine or assist in external respiration

Mammalian diaphragm - this is important

All the **glossus muscles relate to tongue musculature (hypobranchial origin together with the **hyoid muscles)

Extrinsic and Intrinsic appendicular muscles- the former refers to muscles that arise on the axial skeleton or fascia and insert on the girdle or limb; the latter refers to muscles that arise on a girdle or limb and insert more distally on the limb

Extrinsic muscles are primitive - evolved from the locomotor muscles of ancestral vertebrates

Its difficult for me to pinpoint what all muscles you must know. the Following are some muscles, and groups of muscles that I've been reading about (in the lab text). I will not explicitly state what about that muscle I want you to know; I want you to read it your self. when you read about a muscle in the cat, make connections with the shark and necturus (whether you have seen the muscle or not), similarly make connections for the shark and the necturus.

this is not and will not be an exhaustive list

Sartorius longest human muscle – relates to sartorial posture of the tailors (cross legged posture)
Psoas minor is popular as the tender loin
Turtles have no oblique or transverse muscles; they had no use for them as the shell provides rigidity.
Cucularis gives rise to the trapezius muscles of the necturus and cat
rectus cervicis
neck muscles
head muscles
Supra coracoid in urodele is primitive and superficial; birds= large and superficial for wing elevation in flying; and mammals = intrinsic muscle
Homology of deep thoracic muscles

...This page is far from complete...

references (including illustrations on this page):

Kent, G.C. and L. Miller. 1997. Comparative Anatomy of the Vertebrates (8th edition). Wm. C. Brown Publishers.

Wake, M.H. (editor). 1979. Hyman's Comparative Anatomy (3rd edition). The University of Chicago Press.

Walker, W.F. Jr. and K.F. Liem. 1994. Functional anatomy of the vertebrates: An evolutionary perspective (2nd edition). Saunders College Publishing.

links :

chordate zoology lab page

 

Coryphophylax sp.