Fetal Pig Evaluation

Name:

Block:_Title Page - presentation, neatness (5 marks)

— WlkA torrflM. iOrganization - (5 Marks)

Lab 27 - External Features and MuscleDiagram labeled (evaluated for neatness and completeness) (10 Marks)Questions - completion only (4 marks)

Lab 28 - Digestive SystemDiagram of abdominal cavity ioDiagram of bucchal cavity i oQuestions (2 marks)

Lab 29 - Circulatory SystemDiagram of thoracic cavity (10 marks)Diagram of heart ^ ^Point Form Observations of abdominal cavity (10 marks)Questions (2 marks)

Lab 30 - Respiratory SystemPoint Form Observations (10 marks)Questions (3 marks)Lab 31 - Excretory System yPoint Form Observations of abdominal cavity (10 0Diagram of kidney cross-section ,Questions (2 marks)Lab 32 - Reproductive SystemPoint Form Observations («-> ,Questions (3 marks) to)Lab 33 - Nervous SystemDiagram X-section of vertebrae I otitic-}

Practical - Neatness in dissection, attention to detail (25 marks)

1Investigation

27 External Features and Muscles

Introduction Studying the external features of the fetal pig will provide an opportu¬nity to observe several structures that are homologous to pigs andhuman beings, and orient you to structures that will be studied in laterinvestigations.

Muscles enable the movement of body structures and permit locomotion.Most muscles function in pairs that oppose one another. This allows anorgan to ba moved one way and then returned to its original position.

Purpose Tb observe and study the external features and muscles of a fetal pig.

Materialsand

Equipment

MaterialsFetal pigEquipment

disposable glovesstring/cordhand lens/disserting

microscope

paper towelsfreezer bags (for storage)scalpelforcepsprobepinsdissecting trayalcohol squirt bottle

Procedure A. Exeraal features

Obtain a fetal pig and place it in a dissecting tray lined with papertowels. Identify the head, neck, trunk, and tail. From the diagram pro¬vided, find and obearve tha following structures:

Htod—mouth, tongue, external nostrils, nictitating membrane (checkantarior portion of eyeball), eyebrows, eyelid, pinna, auditory meatus,chin hair.Trunk — Two-pairs of legs, wrists, elbow, ankle, knee, toes, hooves,umbilical cord, teats, anus and genital papilla.

Obaarva the articulation of the elbow, wrist, knee and ankle by gentlymoving tha appropriate appendage. Locate the appendage sections thatcorrespond to tha upper arm (brachium), forearm (ante brachium), hand,thigh, shin and foot.

Detennina the sex of your fetal pig. In a female pig the common orificeof the vagina urinary track is located ventral to the anus. Note thatthe folds Gabia) surrounding the orifice come together forming a ventralspike, the genital papilla.

In a male pig the urogenital orifice is located posterior to the umbilicalcord. The penii may ba felt through the belly skin. The scrotum, whichwill contain testaa in a mature male, is located posterior to the hindlege.

72

os y

Eztmtai fmturm of the fisted pig amimuscles of the fbrtkg and shoulder

% region. B« Musdet

)Hie® til® pig on iti right side in the dmsacting tmy* Using a scalpelmsk* & mid-donal mdaum that nma from the base of the head to themiddle of the tack. Extend this incision toward the armpit of the leftforeleg. At the leg join these cuts to an incision that runs down theinside of the leg to the wrist An iadsios that runs completely aroundthe wrist will now allow the skm to be carefuliy peeled from the body.This will require the use of foreeps and a scalpel.

Using the diagram, locate the thin, triangular-shaped muscle (trope-nm) that originates on the dorsal surface and converges to the scapularspine. The deltoid (deltoideus) muscle passes from below the trapeziusto pass over the shoulder. Follow it to its insertion on the leg bone(humerus). The deltoid muscle is a protractor muscle.

Below the trapezius and the deltoid muscles, and posterior to the fore¬leg, a portion of the latissimus dorsi (lata) is visible. It is a major retrac¬tor for the foreleg (arm in humans). TVace this muscle to its point ofinsertion. Note that it attaches to the humerus on the inside of theforeleg beside the armpit The latissimus dorsi passes beneath the tricepsmuscle at the back of the upper leg to reach its point of insertion.

Cut through the latissimus dorsi muscle tissue to expose the tricepscompletely. Note the three points of origin at the shoulder and locatethe tendon that leads to insertion on the lower arm bone (ulna). Thetriceps is an extensor of the forearm.

Locate the smaller biceps muscle on the anterior surface of the humerus.Expose it Completely and note its points of origin and insertion. Thebiceps is'a flexor for the forearm. ¦

73

Questions I. What is the function of the nictitating membrane?2. What is the structural relationship between the fetal pig's toes and

hooves? How many toes per foot are found on the specimen?3. One end of a muscle is attached to a skeletal structure that is in a

fixed position while the other end of the same muscle is attached to askeletal part that is free to move. Which end is the insertion andwhich is the origin?

4. Explain the following antagonistic relationships:a) flexion / extensionb) protraction / retractionc) adduction / abduction

> V}

74

Investigation

28 Digestive System

Introduction The digestive system functions to break down complex molecules infood into small molecules that can be absorbed by the cells lining thedigestive tract.

Purpose To study the digestive system of the fetal pig.

Materialsand

Equipment

Use the materials and equipment listed in Investigation 27.

Procedure A.. Exposing tfie thoracic and abdominal cavities

Place the pig, dorsal side down, in the peper-lined dissecting tray. Tiestring (cord) to one foreleg and pass the string under the tray to be tiedto the other foreleg. Spreed the forelegs as much as possible before tyingthe second foreleg. Repeat this procedure for the hindlegs.

Using forceps, gather a fold of skin end muscle at the midline of thepig's throat, toward the apex of the jaw. Cut through this fold withscissors (Figure 1). Insert the scissors into this opening and cut down theventral midline to the umbilical cord. While this cut, lift thepoints of the scissors upward so that the underlying organs are notdamsgsd,

At this umbilical cord shift tht Una of the cut to om aids of the midlmamud muUmm tha iudsiou posteriorly to the groin* When this is com-pletsdmsfcs a second isaskm that begins slightly anterior to the umbili¬cal cord and extends to the groin. This second incision should parallelthe first cut. This will result in the umbiiic&l cord and* if the pig is male,the urogenital tract, forming a midstrip between the two incisions. Thisfimp may now be folded poeterioriy out of the way after the underlyingumbilical vein is cut. Note and record the location of this vein. Make athird incision laterally acroea the ventral surface. This incision should

i the first incision a few centimetres anterior to the umbilical cord.

Figure L Thsnumbmdlmmmd^cate the hcotwn of ih§ memmm 0expose the internal orgm%&

Using a probe* lift this abdominal flap and locate the diaphragm. Thediaphragm divides the thoracic and abdominal cavities. Using scissorsmake incisions that follow the abdominal side of the diaphragm. Usinga probe and a scalpel, cut the diaphragm away from the thoracic wall.

Bo Organs of the digestive system

Open the abdominal flaps and secure them with pins. Note the shinymembrane* the parietal peritoneum, lining the inner surface of theabdomen. Gently cut this away. Note that the internal organs are joinedby membranes called omenta and that organs are connected to the bodywall by mesenteries.

75

\

J

gall biaaaer •

common bii® dua -

duodenum (smaH mtestma) •

• evopnagus

¦ stomacft

. SPIMO

- pancreas

_ beginning of jeiuno-^eum" (smaH mtestme)

- coils of coton

- desctn^ng colon

• Fig mm 2« Orgam oftiw digmtim From tho dmgrmm prtmdid (Figaro 2\ find mud observe the followmgstnadiiifw m tbt fetol pig ^eeinMiu

trrtr (mmt the mambtr of lobes)gall bladder (often coIowIms^ embedded m ventral surface of the liver)commoii bile ducteeophagus (move liver away from left centre)stomachspleen (to what syftom does it belong?)'

' pancmasmall intoett»

s caeam ^larg® intostlne (colon)

Using scissors, cut through the esophagus as it passes through thediaphragm into the abdomen. Remove the gastrointestinal tract fromthe specimen by cutting the bile and pancreatic ducts, any mesenterytissue from the tract, and by finally cutting the colon at the rectum.

Place your fingers at the junction of the stomach and small intestine(duodenum). Roll this section back and forth in your fingers. Move downthe intestine and repeat this. Compare the feeling. Located at the divi¬sion of the stomach and small intestine is the muscular pyloric sphinoter. This sphincter keeps food in the stomach until digestion is advancedenough to allow the small intestine to continue the process. A similarmuscle/the cardiac sphincter, may be felt where the esophagus leadsinto the stomach.

76

Figurt J. Oral cavity of the fetalpig.

cut surfae® <

naao^aryns -

glottit -

- hard oafatt

- soft palatt

> asopfiagws

»aptgionis

¦ tongut

Using aauon, cot open and flush oat the rtonuch. It ia ofUs witha bilMtainad mucus. Um a hand Una to view tha ruga* or folds on thoinner surfaca of tha stomach. Run your iingars ovsr thoso folds. With ascalpel open three sitaa along the small intastana. Flush thaso and observe,using a hand lens, tha inner lining and its oiUL Run your fingers overthese structures.

Using a probe to break away any mesentery, and pins to secure one end,extend the small intestine. Measure and record its length. Repeat thisprocedure with tha targe intestine;

Insert scissors into tha side of the fetal pig's mouth. Cut through thecheeks and jaw bones on both sides. Open up the oral cavity. Locate thefollowing structures using tha diagram provided (Figure 3):

tongue -¦esophagussoft palatehard palateteeth (may be emerging or beneath the gums)nasopharynxglottisepiglottis

Questions 1. Compare the texture and surface area of the stomach and smallintestine. Explain the reason for the difference.

2. Both the small and large intestines were measured. Which is thelongest? How does the structure of these two organs relate to theirfunctions?

77

Investigatioa

29 Circulatory System

Introduction The ctrculatoi7 system transports many different substances throughout the body. Food nutrients, respiratory gases, metabolic wastes, andhormones are transported to body tissues in blood vessels, the arteriesveins and capillaries. The heart pumps the blood via the arteries to thecapillaries where the exchange of substances between the blood and thetissues occurs. The skeletal muscles provide most of the force that movesthe blood from the capillaries via the veins back to the heart.

Thia study can be used in conjunction with the more detaileddissection of the mammalian heart. Investigation 37.

Purpose lb study the circulatory.system of the fetal pig.

Materialsand

EquipmentProcedure

Use the materials and equipment listed in Investigation 27.

Open the thoracic cavity completely, Thia may require further cutting.Secure these flaps. A clear view of the heart is likely blocked by thethymus gland. Note the location of the thymus remove it com*pletely. Note the pericardial sac around the heart. Careftilly remove it.From the diagram provided (Figure 1) find and obaerve the structureslisted below oa the fetal pig specimen:

right atriumleft atriumright ventricleleft ventriclepulmonary trunkpulmonary artery

coronary arteryaortic archsuperior vena cavainferior vena cavaductus arteriosus

Nots ths position of the hesrt and then remove it completely from thebody cavity. Cut the vessels about 1 cm from ths hesrt Place the heartin the dissecting tray in a position .similar to ths one it had in thethoracic cavity. Using a scalpel, dissect the heart into a frontal and hindsection. This is accomplished: by starting ths incision high on the rightatrium, approximately 5 nun back from ths ventral surface. Continuethia incision downward to the apex. Open the heart to check that yourincision exposes both the right atrium and right ventricle. Repeat thisprocedure from the left atrium to the apex. Remove the front of theheart by making an incision through ths septum that divides the rightand left chambers.

From the diagram provided (Figure 2) find and observe the structureslisted below in the fetal heart:

right ventricleleft ventriclepulmonary semilunar valveaortic semilunar valveforamen ovale

right atriumleft atriumchordae tendiaeaebicuspid valvetricuspid valve

78

C )

juguiar veins ¦

supenor vena cava -

right ai/ium -

right venthda -

tettcofonaryartery and vein

inferior vena c®v®-

carotid arteries

aortic arcn

pulmonary trunkductus arteriosuspuir nonary artery

leftairiuri

left ventride

Figum L The hmrt md rmgw1vtsmli of the cirmhtory system

foramen 0¥aje

right atrium

trla^pid vaSv®

chorda®tendinea®

right vtntridt

aorticsemiiunaf v^ve

left atriumpulmonarysemilunar valve

bicuspid valve

left ventnde

Figure 2* Stmeturts within thefi'tal heart

FVgurt J. Mqjor vmmk ofth*abdomifml cmify

T\iih th# MM portton of the heart over. Locate the aortic arch, pulrao-nary arterieiv pnlnwnary ¥emat superior vena cava and inferior venacava.

Locate the severed end erf th® mperior vena cava. TVaet it anteriorly tothe point that it branchei. Note that two pain of branches come fromth# neck arm Theee art thmjuguMy mim. Move these to one aide andlocate th# mrotid mterm that carry Mood to the head, TVace these back

•, to th# aortic ardL >

By observing th# abdominal cavity, the pathway of the aorta and infe¬rior vena cava may be traced. Prom th# diagram provided (Figure 3),find and obetne th# strwturet listed below in the fetal pig specimen:

aorta • iliac arteryinferior vena cava iliac veinrenal artery umbilical arteryrenal vein umbilical vein

Question# 1. What is the function of the ductus arteriosus?2. The major arteries are often located deeper into the body cavity than

are major veins. Why is this thaease?

80

Investigation

30 Respiratory System

Introduction The respiratory system functions to transport oxygen and carbondioxide to and from the lungs. Here oxygen diffuses into the blood fortransport to the body tissues. Carbon dioxide, a by-product of cellularrespiration, diffuses from the blood into the lungs and is exhaled.

Purpose To study the respiratory system of the fetal pig.

Materialsand

EquipmentProcedure

Use the materials and equipment listed in Investigation 27.

Extend the thoracic incision anteriorly to the base of the fetal pig jaw.Spread this incision to expose the underlying tissue. From the diagramprovided, find and observe the structures listed below in the fetal pigspecimen:

larynxtracheabronchi

diaphragmlungs

Rtspimiory itmetums of the fktol

trsehea

thymus gland

bronchioles

secondary broncnus *

thyroid gland

left phmary bronchus

diaphragm

lobes of lung

81

Using a scalpal, make an incision into the trachea at the point where itbranches into the bronchi. Continue the incision anteriorly to the lar¬ynx. Note the toughness of the trachea, the shape and position of carti¬lage, and the structure of vocal cords in the larynx. Use a hand lens toobserve the texture of this air duct. Pass a probe up the trachea and outthe glottis. Check the mouth to see the top of the probe.

Count the number of lobes on each lung of the fetal pig. Note the attachedmesentery tissue. Carefully remove one lung. Observe it using a handlens or dissecting microecope. Locate the bronchus entering the lung.Using a scalpel, open the bronchus to see it begin to rebranch repeatedlyinto bronchioles. Cut a section through the lung and note the density ofthis tissue.

t QuestioM 1. What is the function of the tracheal cartilage? What shape is it?v 2. How many lobes does each lung of the fetal pig have?

3. The bronchus subdivides into a series of smaller ducts that termi¬nate in many sac-like end structures. What are these ducts called?

82

Investigation

31Introduction

Purpose

Materialsand

EquipmentProcedure

f frinnr\t mtritrtur** nf thjt fetaL DC#

I

Excretory System

The excretory system functions to remove nitrogenous wastes from thebody. Nitrogenous wastes are filtered from the body by the kidneys,after which the urine that is formed is temporarily stored in the urinarybladder until it is expelled.

This study can b« used in conjunction with Investigation 47, Kid¬ney Structure.

To study the excretory system of the fetal pig.

Use the materials and equipment listed in Investigation 27.

Open the abdominal flaps of the fetal pig and secure these to expose theabdominal cavity. Fold the midflap of tissue downward. This tissuecontains the umbilical cord, bladder, and, if the pig is male, the penis.Locate the kidneys, one on either side of the spins, high on the dorsalwmlL Not# that the kidneys are behind (or outside) the peritoneum.

Using a scalpel and forceps, carefully remove the peritoneum. From thediagram provided, find and observe the structures listed below on thefetal pig specimen;

adrenal gland allantoic (urinary) bladderkidney umbilical cordrenal artery urethrarenal vein penis (on the male specimen)ureter genital papilla (on the female specimen)

83

oUsing a scalpel, make an incision into the bladder at a point just poste¬rior to where a ureter enters the bladder. Continue the incision posteri¬orly, and slightly downwards, towards the urethra.

Locate the points where the ureters enter the bladder. Note their appear¬ance. Observe the urethra and note changes in wall thickness, indicat¬ing a sphincter.

Using scissors, remove one kidney. Dissect the kidney into frontal andhind sections. Tb accomplish this, make the first incision ventral to thepoint where the ureter leaves the kidney. Using the diagram provided,find and observe the structures listed below on the fetal kidney:

.renal cortex renal arteryrenal medulla renal veinrenal pyramuls ureterrenal pelvis

Questions 1. Prior to birth, does .the urethra function? If not, how would wastes beremoved?

2. What is the function of the urethral sphincter?

S

84

Investigation

32 Reproductive System

Introduction The function of the male reproductive system is to produce sperm andplace them in the female's reproductive tract. The female reproductivesystem produces egg cells, receives the sperm and nourishes the develop*ing offspring.

This study can be used in conjunction with the study of the humanreproductive system, Investigation 60.

Purpose To study the reproductive system of the fetal pig.

Materialsand

EquipmentProcedure

Figur* 1. Tht rtproductw* tyattmof tht molt fetal pig.

Use the materials and equipment listed in Investigation 27.

A. Made fetal pig

Locate the urogenital orifice poeterior to the umbilical cord. Using scis¬sors, carefully cut the mid-ventral strip from the orifice posteriorly.Fold this tissue to expose the penis. From the diagram provided (Figure1), find and observe the structures listed below on the fetal pig:

penisurethrapreputial orificeductus deferens

prostate gland (may be difficult to see)bulbourethral glandseminal vesicles

Using a probe, trace the ductus deferens to the scrotum. Using a scalpel,make an incision in the scrotum to expose the testes. Locate a testis,epididymis, and the gubernaculum. The gubemaculum is the cord pos¬terior to the epididymis that runs to the scrotum.

85

Ftgmrtl Tht npndttcta* tyttm B. FenuU fetal (rifof th* ftmaU ftiai pig.

Loest* th* Y-«hap*d (biputito) uterua. Uaing a scalp*! and scissors,opan tha palTie gMla to azpoaa tha urethra and th* vagina. From thediagram provided (Figure 2\ find and ofaaerve the structures listed belowon th* fatal pig:

inftindibulumvaginabroad ligament

ovane*body of uterushorns of uterus

Using a probe, locate the sit* where the urethra and vagina merge to acommon (urogenital sinus). Use a scalpel to open this sinus.Locate tha urethral opening, clitoris, cervix of the uterus.

Qaestton* I. Explain why th* testes are located in the scrotal sac.2. What may baona function of tlie gubernaculum?3. What are the structural differences between a human and pig uterus?

What does this suggest?

86

Investigation

33 Nervous System

Introduction The nervous system coordinates the activities of all the body's orean-systems. This is accomplished primarily by nerve impulses. Coordina¬tion of the body's systems takes place by means of impulses transmittedfrom the brain and the spinal cord to muscles and glands. These impulsesare initiated as a result of impulses sent to the brain and spinal cordfrom sensory receptors. These receptors detect changes occurring in theinternal and external environment. The body's response to these changesis coordinated by the nervous system.

This study can be used in conjunction with the dissection of amammalian brain (Investigation 49).

Purpose To study the nervous system of the fetal pig.

Use the materials and equipment listed in Investigation 27.

With tha pig dorsal sida down, open both thoracic and abdominal flaps.I/Kate tha spinal column and follow it anterioriy towards the lungs.Shift tha lungs slightly and locate a slender white cord ths* appears tohave lumps. This is tha sympathetic nerve trunk (Figure 1). The sympa¬thetic nerve trunk lies outside' the central nervous system (brain andspinal cord) and is part of the peripheral nervous system.

Select e site along the spine (e.g., the thoracic pectoral area) and removeany organs blocking your view of the spine. Using a scalpel, expose thespine and locate any emerging nerves. Select one and trace it as far asyou can into the body.

t Place the pig dorsal side up in your dissecting tray. Locate the thoracicregion and remove the skin and muscle to completely expose 10 mm ofthe vertebral column. Note the thoracic nerves extending from the spineto the muscles.

Using forceps to grip the spinous process and scissors for cutting,open the vertebral canal by cutting off the vertebral arch. Note the duramater, the outermost covering of the brain and spinal cord. Locate avertebral joint and use scissors to cut through this connection. Makecuts on both sides of the spine from this initial incision between vertebrae.Fold the spine section upward for viewing and secure it with a probe.

Make an incision in the dura mater and peel it to one side. Using ahand lens, locate' a dorsal root, dorsal root ganglion, ventral root, cen¬tral canal, and also note the external and central spine colouration(Figure 2).. ... '

87

Materialsand

Equipment

Procedure

B8i ¦ i»»pxi»o

jvs •tppnn ptr* rauqaMB snndmX) mp jo noiptny wp rt >Ixn j*ani tq; jo AOpauk panoj «p jo aojiDtny mp t) "£

^•3au»£n> cnp joj aotfMi aip «i jwx^ *»*q*nn ao|pw •tnds mp jo (|«aM)za '[mpoao) nopiod tptq^ 'Z

^Mmp BMnniqinm »iu»u apaq^vdnuCs aip m 4(tduini„ atp an ?trq^ *1 niO|9San^

uaiuijadiSrd aqtjo xnXnqdona aq) m aoado 9; aaaq* aaJaaqo pm opn aqojda lAcin 'paivaoi ft }i(a «np saq^ fnaqwis aq) jo nopvaoj aq) 0) {ipoaApen joua^ua ^qa a ti i^uaa jna ipppu aq^ tprtt fitmado aqip tzanp•a^ana aqx 'itapQia laAo'aqj 0} jouaisod poa luroaA at Jtoptn* ponojaqx 'xpy wiyyvftns aq) 0) Sctoado aq) poa moptnm puntu aq) 8)1307

*T ».

•otopinm jdoo aq) at erqj, •paaoortd tailaadan aq) q»p{M tnojg ajoq n«utt aq) ank isaq) ^jpoapi vaq)pm £jpo)aaaq)moqv trnjop pea tipia <»»B>ymtaq) 'aaiqwn LtJifpua wp aawuajiqiqano -ijuiao jaa anqmn aq)>a an aq) a)OK'K'*ajG9',zT*n^nauoptontado anp atopia -agaiqwam aq) a) paqjf pa ai qafqm nrjjuu/ aq)go Smqaajq pio^a o) dq, 'aoajqoata sfnadiiuC) aq) aaomai 'adaajoj poaadooausnn Smpaaaip jo aoaj poaq a ttna/i ¦anuqmais aptadnti) aq) joai»aq)a)0]j'an)aamXjo)ipniaq)/)pBBja)noaq)0)|ai)oaAajapaapu,¦rvajftutw mtvdui# aq) aaodxa o) aipaam ^io)|pna aq) taqnnoxznaanaap aaooM •uoaapa poa aqojd a fdnqi fojaQ ivnaa ipp 0) iU)BaAiptqt aq) poa npaam Xacnqma aq) aaodxa o) otnnd aq) aAOnxaj qadiasaa poa ajoaape Sbiba vte) inpjaaaHJ aq) m apt* a)i no Bid aq) aaaj^