Download Worksheet for Morgan/Carter Laboratory #24

Worksheet for Morgan/Carter Laboratory #24
“Vertebrate Anatomy III – Excretory, Reproductive and Nervous Systems”
BE SURE TO CAREFULLY READ THE INTRODUCTION PRIOR TO ANSWERING THE QUESTIONS!!!
You will need to refer to your text book to answer some of the questions on this worksheet.
EXERCISE 24.1: The Excretory System
Procedure
1. Examine the fetal pig and identify the following structures: kidney, renal artery, real vein and parietal
peritoneum (thin membrane covering the kidney.
2. Dissect the kidney itself, per the instructions in the lab manual. Identify the following structures: renal
cortex, renal medulla, renal pyramids, renal pelvis and the ureter. Using Figure 24.1 in your lab manual,
draw a picture of a cross-section through the kidney in the box below and label each of these parts.
Cross-section through the Kidney
3. Identify the urinary bladder, umbilical arteries and the allantoic stalk.
Results
Use your text book and lecture notes to draw a picture in the box below of a single nephron of the
kidney and label the following parts: glomerulus, proximal convoluted tubule, descending limb of the
loop of Henle, ascending limb of the loop of Henle, distal convoluted tubule and the collecting duct.
Drawing of a Nephron
Discussion
In the table below, refer to your text and your notes to identify the roles of the following hormones on
renal function. Note the results on fluid retention/expulsion and subsequent effect on blood pressure.
Hormone
ADH
Aldosterone
Angiotensin
Atrial Natriuretic
Peptide
Mode of Action
Fluid Effect
Blood Pressure Effect
EXERCISE 24.2: The Reproductive System
NOTE: Your group will have either a male or female pig. Dissect the pig that you have and then study the
parts of the opposite sex.
Procedure
1. Carefully follow the dissection procedures as outline in the lab manual:
Steps for dissection:
A. The penis is located in a flap of the ventral body wall caudal (toward the tail) to the umbilical
cord. Feel for the penis below this flap of skin. Hold the flap between your fingers and feel for
the cord-like penis just below the skin.
B. Begin at the urogenital opening , the preputial orifice, and make a longitudinal incision just
through the superficial skin and toward the tail. Use a probe to locate and expose the penis.
2. Using Figure 24.2b as a guide, identify the following structures: ureters, ductus deferens, scrotum
testes, epididymis, urinary bladder, seminal vesicles and prostate gland.
Discussion
1. A vasectomy is the most common type of male sterilization used by men for birth control. What is
done in this procedure?
2. Which structures are part of BOTH the reproductive and urinary systems in the male?
3. Explain why the testes are located OUTSIDE the body of the animal in the adult male.
In the Table below, describe the roles of these structures:
Organ/Duct
Activity or Secretion or Role
Testis
Epididymis
Ductus Deferens
Urethra
Penis
NOTE: once you complete your dissection of your pig, go to a pig of the opposite sex for study.
Lab Study A – Female Reproductive System
NOTE: Your group will have either a male or female pig. Dissect the pig that you have and then study the
parts of the opposite sex.
1. Use Figure 24.3a for reference in this dissection. Carefully follow the dissection procedures as outline
in the lab manual and identify the following structures: ovaries, uterine tubes (not a uterus as in
humans), horn of the uterus, body of the uterus, cervix and vagina.
NOTE: once you complete your dissection of your pig, go to a pig of the opposite sex for study.
Results
Using the structures identified above, describe the pathway of an egg from the ovary to the outside of
the body.
Using Figure 24.3b, draw a picture of the female reproductive organs in the box below and label the
following parts: ovary, uterine tube, uterus (horn, body, cervix), vagina, orifice of the urethra and
vaginal vestibule.
Enlarged View of Female Reproductive System in Fetal Pig
Lab Study C – The Uterus of an Animal
Procedure
1. Observe the uterus with one of the uterine horns opened.
2. If it is not already dissected (it may or may not be), using scissors, carefully cut into the chorionic
vesicle, the sac-like structure surrounding each of the fetal animals. Note that the chorionic vesicle is
composed of two fused membranes: the chorion and the allantois.
Results
Using your text book as a guide, identify the role of the following extraembryonic membranes:
Extraembryonic Membrane
Role
Chorion
Allantois
Amnion
Yolk or Yolk Sac
Discussion
1. How does the female anatomy of a pig, cat or dog, which has multiple fetuses (“a litter”) differ from
that of a human? (e.g. uterine tube, uterine horns and body of the uterus)
2. Describe the differences in the arrangement of the vagina and urethra in the fetal pig and the human.
3. Tubal ligation is a common form of human female sterilization. How does this work?
EXERCISE 24.2: Nervous Tissue, the Reflex Arc and Vertebrate Eye
Lab Study A: Nervous Tissue and the Structure of a Neuron
Procedure
1. Using the medium powered lens on your compound light microscope, scan a prepared slide of a
spinal cord neuron smear. Locate the “star-like” neurons (nerve cells). In the box below, draw a picture
of what you observe. Look for individual neurons and their nerve cell processes (axons and dendrites)
which will be very short since they get cut off during slide preparation.
Examples of Neurons in the Spinal Cord
2. Using Figure 24.5 and your text as a guide, draw a typical multipolar neuron in the box below and
label the following parts: cell body (soma), dendrites, axon and axon terminals.
Neuron and Parts
Lab Study B: The Reflex Arc and Structure of the Spinal Cord
1. Using Figure 24.6, in the box below draw a picture of a cross section through the spinal cord and label
the following parts: doral root (sensory), ventral root (motor), dorsal wing of gray matter, ventral wing
of gray matter, cental canal, sensory neuron of dorsal root, motor neuron in ventral root, interneuron
and the dorsal root ganglion.
Note: on your drawing, be specific about the location of the cell bodies of the neurons involved.
Drawing of Spinal Cord and Components of a Reflex Arc
Results
List the sequence of three neurons involved in a typical reflex arc of the spinal cord.
Discussion
Most reflexes involve a specific sensory receptor (heat receptor, touch receptor, pain receptor, etc.),
several sensory neurons, several interneurons, several motor neurons and their ultimate effector organs
(muscles or glands). Describe a reflex arc if you accidentally place your hand on a hot stove.
Lab Study B: The Reflex Arc and Structure of the Spinal Cord
Procedure
CAREFULLY follow the instructions on the dissection as written in your lab manual!!
1. Locate the following structures: cornea, optic nerve (you may have to remove muscle to find it),
sclera, lens, ciliary body, lens, vitreuous humor, retina, iris and pupil.
6. The ciliary body is a small smooth muscle that pulls on the lens to change its curvature. What is the
purpose of this muscle?
7. The iris has its own smooth muscle that can alter the size of the pupil. What is the role of the pupil
and how does this muscle accomplish this task?
8. What is the function of the retina of the eyes?
Results
Starting with the cornea, list the structures using arrows that light passes through on the way to the
retina.
Discussion
1. Using your text or another reference, describe the following eye impairments:
Vision or Eye Impairment
Myopia
Hyperopia
Astigmatism
Cataract
Vision Deficit or Impairment
REVIEWING YOUR KNOWLEDGE
There are three different tunics of the eye. In the table below, note the subdivisions that make up each
eye tunic and describe their important functions.
Tunic
Subdivisions
Fibrous tunic
Sclera
Cornea
Vascular Tunic
Choroid layer
Ciliary body (muscle)
Iris
Retina
Photoreceptor layer
Function