BioScience.pk App
www.bioscience.pk
Put vital info into the palm of your hand.
ASH Job Center
www.jobcenter.hematology.org
By American Society of Hemotology

ANIMAL ANATOMY: POSITION AND FUCTIONS OF CANALS AND DUCTS

Published in Zoology
Monday, 26 June 2017 21:38
Previously we discussed about various exocrine glands in and foramen in animals. This topic covers about various principle ducts and canals present in animal body and their location and their functios.
 
ANAL CANAL
Location: Rectum of Mammals
Function: It extends from the pelvic floor downward and posteriorly to the anus.
 
BIDDER’S CANAL
Location: Frog’s kidney sperms.
Function: It connects testis to kidney and conducts
 
BILE DUCT
Location: Vertebrates
Function: It runs from gall bladder to duodenum through which bile flows.
 
 bile duct11
 
CANAL OF SCHLEMN
Location: Mammalian eye
Function: It lies near the junction ofcornea and sclera, this canal passes circularly around the cornea, and drains the aqueous humour.
 
SCHLEMN CANAL12
 
CENTRAL CANAL (CEREBROSPINAL CANAL)
Location: Spinal cord
Function: It is situated in the centre of gray matter and extends entire length of the cord. Cerbrospinal fluid flows in it.
 
CERVICAL CANAL
Location: Uterus
Function: Canal of cervix of uterus
 
COCHLEAR CANAL (SCALA MEDIA)
Location: Internal ear of mammals
Function: It is middle canal in the cochlear duct filled with peri lymph
 
COLLETING DUCT
Location: Kidney of mammals
Function: These are many and collect urine.
 
CYSTIC DUCT
Location: part of bile duct in vertebrates,
Function:  which leads from gall bladder receives branches from various part of the liver and it eventually forms the common bile duct.
 
DUCT OF RIVINUS
Location: Salivary glands of mammals
Function: Ducts of sublingual glands (Sublingual ducts) lie just beneath the floor of the mouth and open into the floor qf the mouth.
 
ENDOLYMPHATIC DUCT
Location: Internal ear of mammals
Function: It is a small short duct connected with saccule and end blindly in the endo lymphatic sac.
 
EUSTACHWN TUBE (AUDITORY TUBE)
Location: Middle ear of all land vertebrates
Function: It connects middle ear with pharynx.
 
HAVERSIAN CANALS
Location: Bones
Function: These are longitudinal canals found characteristically in long bones.
 
Haversian canals14
 
HEPATIC DUCT
Location: Liver of vertebrates
Function: It originates from liver cells and unites with the cystic duct from the gall bladder to form the common bile duct.
 
hepatic duct9
 
HYALOID CANAL
Location: Eye of mammals
Function: It extends between optic disc and the lens.
 
INGUINAL CANAL
Location: Reproductive organs of male mammal.
Function: It connects abdominal cavity to scrotal cavity.
 
inguinal canal6
 
LACRIMAL DUCTS
Location: Eyes of man
Function: These are two (superior and inferior) connect lacrimal gland with lacrimal sac.
 
LACTIFEROUS DUCTS
Location: Mammary glands of placentals
Function: These carry milk from mammary glands to the tip of
 
LAURER’S CANAL (LAURER STIEDA CANAL)
Location: Reproductive organs of liver fluke
Function: It is temporary copulatory canal which opens on the dorsal body surface.
 
LYMPHATIC DUCT RIGHT
Location: Thorax of vertebrates
Function: It is a short duct receives lymph from the right side of the head, the right upper extremity and the right side of the thorax.
 
MANDIBULAR CANAL
Location: Lower jaw of mammals
Function: It originates from mandibular foramen for in- ferior alveolar vessels and nerve and lies on the inner surface of each ramus.
 
NASOLACRIMAL DUCT
Location: Nose
Function: It connects lacrimal sac with inferior nasal meatus.
 
NEURENTERIC CANAL
Location: Vertebrate embryo
Function: It is a canal joining the primitive gut with the cavity of neural tube.
 
PANCREATIC DUCT (DUCT OF WIRSUNG)
Location: Pancreas
Function: The duct which conducts enzymes from the pancreas into the duodenum.
 
PAPILLARY DUCT (DUCT OF BELLINI)
Location: Kidney of mammals (part of renal tubule)
Function: These open on the tip of renal papilla and pour their contents into a minor calyx of the renal pelvis.
 
PAROTID DUCT (STENSON’S DUCT)
Location: Salivary gland of mammals
Function: It passes anteriorly to pour into the yes- tibule of the mouth, opposite the upper second molar tooth.
 
SEMICIRCULAR DUCTS (CANALS)
Location: Internal ear of vertebrates
Function: These are filled with endolymph and concerned with equilibrium.
 
SUBMAXILLARY DUCT (WHARTON’S DUCT)
Location: Salivary gland of mammals
Function: It extends from the anterior end of each submaxillary gland and opens into the floor of the mouth on each side of the frenulum.
 
THORACIC DUCT
Location: Thorax and Abdomen of mammals
Function: The chief collecting duct of lymphatic system receive lymph from lacteals. It lead towards left subclavian
 
thoracic duct7
 
THYROGLOSSAL DUCT
Location: On the floor of pharynx in mammals
Function: An embryonic duct between thyroid and pharynx. it disappears in adults.
 
VERTEBRATERIAL CANALS
Location: Cervical vertebrae of mammals, birds and reptiles
Function: These canals are found at the base of transverse processes of cervical vertebrae for the passage of cervical blood vessels and nerves.
 
VOLKMANN’S CANAL
Location: Long bones of mammals
Function: These are transverse canals, connecting Haversian canals. These carry blood.
 
Volkmanns canal8

STRUCTURE OF POLYSTOMELLA (ELPHIDIUM)

Published in Zoology
Friday, 14 April 2017 17:01
Elphidium is a marine form. It is found creeping on Sea weeds to a depth of 300fathoms
Phylum : Protozoa
Class : Rhizopoda
Order : Foraminifera.
 
Structure
 
Elphidium is also called 'Polystomella is a 'dimorphic rhizopod'. It is a unicellular microscopic protozoan, and" 1 mm in diameter It is pale yellow in colour. It lives in marine water. The body is covered by a shell. The shell is biconvex. The first formed chamber is proloculum. The shell contains spirally arranged V shaped chambers. Hence it is called "polythalamus or multilocular They overlap one another. These chambers show 'openings' hence it is perforate Through these openings cytoplasm will come out. The cytoplasm is produced into a number reticulopodia. which will form a network. From hinder end of each chamber cytoplasmic processes will develop. They are directed backwards. They are called retral processes'.
 
The chambers are filled with the cytoplasm.
  1. The cytoplasm contains one or many nuclei.
  2. Contractile vacuole is absent.
  3. Mouth is absent.
  4. Cytoplasm contains food vacuoles. They take up the process of digestion.
Dimorphism: Polystomella exhibits dimorphism. The individual occurs in two distinct forms.
1. Megalosperic form.
2. Microspheric form.
  1. Megalospheric form: Its proloculum is big in size. A single large nucleus is present in one of the chambers. It takes up sexual reproduction.
  2. Microspheric form: Its proloculum is small in size. Many nuclei are present in the cytoplasm. This form reproduces by asexual reproduction.
Locomotion and Nutrition:
Polystomella show slow creeping movements with the help of reticulopodia. It is a holozoic feeder. These Pseudopodia will capture the prey. When it comes in contact with the prey, it kills the prey by secreting toxic substance. The prey is digested in the food vacuole the digested food is absorbed by the cytoplasm.

SCOLIODON - INTERNAL EAR

Published in Zoology
Friday, 14 April 2017 16:07
In Shark 3 pair of internal ears are present. They are organs of equilibrium and hearing. The middle and external ears are absent. The internal ear is a complex structure. It is called the membranous labyrinth. It is present in the auditory capsule of the cranium. It is covered by cartilaginous labyrinth. A space is present between the membranous and cartilaginous labyrinths. It is called peri lymphatic space. It contains peri lymph. It protects and transmits vibrations to the membranous labyrinth. Connective tissue extends from the Cartilaginous to the membranous labyrinth.
The membranous labyrinth has laterally compressed vestibule which is divided into two chambers,
a) The upper narrow utricles,
b) Lower wide sacculus.
 
The two chambers are connected with each other by a wide passage, the sacculoutricular duct. The sacculus gives off a conical projection from its lower side, called lagena. A narrow canalarisesfrom the dorsal side of the sacculus called ductus endolymphaticus. It pierces through the roof of the cranium and open out by a minute pore. Before it opens out the duct dilates into saccus endolymphaticus. Three semicircular ducts are present. They are called the external, anterior and posterior semicircular canals. . The external canal is horizontal and the other two are vertical in position. All the semicircular anals open into the utriculus at both of their ends. One end of each canal is dilated into oval ampulla. The ampullae of the anterior and the external canals lie close together towards the anterior end of the ear.
 
The cavity in the membranous labyrinth is filled with a fluid Endo lymph. Six sensory patches are present in the wall of the internal ear.The sensory patches' of the ampullae are called the "cristae". The sensory patches of the utriculus, sacculus and lagena are called maculae acousticae They contain neurosensory and supporting cells. Each neurosensory cell bears a sensory hair at the free end, and passes into a nerve fiber at the other end. The nerve fibres join the auditory nerve. The sensory hair are much longer cristae than in the maculae. They are enclosed in a gelatinous substance. The gelatinous substance is called the cupule. In Maculae the otolithic membrane has in its outer part minute crystalline bodies called otoliths.
 
They are formed of calcium carbonate.
 
Functions:
  1. The cristae detect turning movements of the head.
  2. The maculae in the utriculus and sacculus detect changes in the position of the body at rest and in the forward movement. With a change in the position of the body, the otoliths change their position due to gravity and bring pressure on the underlying sensory hairs and this stimulates the neurosensory cells. The body position is corrected. Thus equilibrium is brought forward.
  3. The maculae & lagena will detect under water sound vibrations to some extent.

STRUCTURE OF SHARK EYES

Published in Zoology
Friday, 14 April 2017 13:38
SHARK EYE (SCOLIODON EYE) – ANATOMY
 
Shark two eyes are present on the head. They are located in the orbits and are laterally directed.
 
The eye is large in size and elliptical body. It is a hollow structure. It is covered by three coats.
 
1) The fibrous outer coat is thick. It protects the eyeball and maintains its form. It has large posterior scierotic and anterior transparent cornea The sclerotic coat is cartilagenous.lt is hidden in the orbit. A small portion is visible externally, called the white of the eye. The cornea is composed of connective tissue. It is covered by a transparent epithelium called conjunctiva. The cornea permits the light to pass into the eye.
 
2) The middle coat has three distinct regions.
   a) The choroidis composed of a soft connective tissue with pigment cells and blood vessels
   b) The choroid is adjacent to the retina and contain light reflecting crystals called tapetum lucidium.
   c) At the junction of the sclerotic and the cornea the middle coat, abruptly bends into the cavity of the eye as "iris", it has slit called pupil. Behind the periphery of the iris, the middle coat is thicker, and less pigmented and is called the ciliary body. It has no muscles and plays no role in accommodation.
 
3) The retina is very delicate and lines the whole of the middle coat, it has three regions.
   a) optic part is in contact with the choroid. It is sensitive to light,
   b) The ciliary and
   c) Iridial parts are non sensory parts.
 
The point of the retina from where the optic nerve leaves the eye is called the blind spot. This region has no receptors. It is not sensitive the light. The retina contains rods. The cones are absent. The fish is colour blind. Its eye is adapted to "dim light" vision.
 
A solid transparent crystalline lens, lies just behind the pupil. It is held in place by a gelatinous suspensory ligament. It extends from the lens capsule to the ciliary processes. The lens divides the cavity of the eye into two chambers. The anterior smaller aqueous chamber and the posterior larger vitreous chamber. The aqueous chamber is partly divided into anterior and posterior parts by iris. It has aqueous humour. The vitreous chamber is filled with the vitreous humour. The humours keep the eye inflated and aid in focusing Sight rays on the retina  of shark.
 
The eye is protected by three lids. The upper end lower lids are folds of skin are immovable. The third eyelid, the nictineting membrane is well developed. It covers the eye fully. It is a growth of the anterior region of the lower eyelid. Lacrimal gland is absent.

Appleton and Lange Review of Anatomy - 6th Edition

Published in Downloads
Thursday, 05 May 2016 20:55
Description: Offers medical students the best available review of all major topics in anatomy for course review as well as preparation for the USMLE Step 1.

The new edition features over 800 exam-type questions & answers, discussions of each answer, a 100-question practice test, improved illustrations, and more high-yield facts.

More than 800 USMLE Step 1-type questions

100-question practice test, Detailed explanation for each answer, Rationales for right and wrong answers.

The most comprehensive, useful, and up-to-date USMLE Step 1 preparation for anatomy questions, Learn more in less time, Evaluate your areas of strength and weakness, Reinforce knowledge, confidence, and skills.

Clinical Anatomy by Regions - 9th Edition

Published in Downloads
Monday, 02 May 2016 15:41
Description: Widely praised for its clear and consistent organization, abundant illustrations, and emphasis on clinical applications, Clinical Anatomy by Regions delivers the user-friendly features and expert perspectives that have made the textbook one of the top teaching and learning resources for those seeking insights into the practical application of anatomy.

Ideal for medical, dental, allied health, and nursing programs, this book guides students through the fundamentals of human anatomy, explaining the how and why behind each structure, and offering readers the hands-on guidance they need to make sound clinical choices.


Organized by body region from surface to deep structures, this new edition features:
  • Updated design and layout allowing for a shorter, more focused text
  • Enhanced color illustrations and art program to facilitate visual learning
  • Basic Clinical Anatomy sections with essential information on gross anatomic structures of clinical significance
  • Chapter Objectives that focus students on material most important to their preparedness for the patient encounter
  • Clinical Notes highlighting the clinical importance of anatomical information
  • Embryologic Notes with insight on developmental anatomy
  • Numerous examples of clinical images to support the text
  • Surface Anatomy sections explaining surface landmarks of important structures
  • Online E-Book and Interactive Question Bank
 

Gray's Anatomy for Students - 2nd Edition

Published in Downloads
Monday, 02 May 2016 15:36
Description: It didn't take long for students around the world to realize that anatomy texts just don't get any better than Gray's Anatomy for Students. Only in its 2nd edition, this already popular, clinically focused reference has moved far ahead of the competition and is highly recommended by anyone who uses it. A team of authors with a wealth of diverse teaching and clinical experience has updated and revised this new edition to efficiently cover what you're learning in contemporary anatomy classes. An improved format, updated clinical material, and remarkable artwork by award-winning illustrators Richard Tibbitts and Paul Richardson make anatomy easier than ever for you to master. Unique coverage of surface anatomy, correlative diagnostic images, and clinical case studies demonstrate practical applications of anatomical concepts. And, an international advisory board, comprised of more than 100 instructors, ensures that the material is accurate, up to date, and easy to use. To further enhance your learning experience, you'll have access to the entire book online, with additional content, interactive exercises, and more. Take your Anatomy learning even further with other members of the Gray's 'family' - Gray's Atlas of Anatomy, Dorland's/Gray's Pocket Atlas of Anatomy, Gray's Dissection Guide for Human Anatomy, and the new edition of Gray's Anatomy for Students Flash Cards.

Clinical Anatomy Made Ridiculously Simple pdf Edition 3 by Stephen Goldberg

Published in Downloads
Sunday, 01 May 2016 11:23

Description: Clinical Anatomy Made Ridiculously Simple pdf Edition 3 by Stephen Goldberg

Useful Sites

  • NCBI

    National Center for Biotechnology Information
  • LTO

    Lab Tests Online® by AACC
  • ASCP

    American Society for Clinical Pathology
  • ASM

    American Society for Microbiology
  • The Medical Library®

    Project of BioScience.pk

Sponsored Links

ASH Job Center
www.jobcenter.hematology.org
By American Society of Hemotology
BioScience.pk App
www.bioscience.pk
Put vital info into the palm of your hand.
Online Digital Library
www.bioscience.pk
Free Downloads Medical Books.
Advertisement

Sponsored Links

SiteGround
www.siteground.com
Web Hosting Services Crafted with Care!
Make money online!
www.adf.ly
Use a URL shortener service that pays.
ASH Job Center
www.jobcenter.hematology.org
By American Society of Hemotology
BioScience.pk App
www.bioscience.pk
Put vital info into the palm of your hand.
Online Digital Library
www.bioscience.pk
Free Downloads Medical Books.
Daily Science
www.bioscience.pk
The Science News app that will get you to the breaking news.

Connect With Us

Contact Us

All comments and suggestions about this web site are very welcome and a valuable source of information for us. Thanks!

Tel: +(92) 302 970 8985-6

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Website: https://www.bioscience.pk

Our Sponsors

The Physio ClubB2BPakistan.com

By using BioScience.pk you agree to our use of cookies to enhance your experience on this website.