Lab 5.1 Comparative anatomy

Structures to compare GI vs Excretory vs Circulation

transverse plane

top and bottom

coronal/frontal plane

front and back halves

sagittal plane

right and left halves

anatomical planes (sagittal, coronal, transverse)

anatomical plane in pig

which plane?

a) sagittal ???

where are the kidneys relative ot the sternum in human
A. Superior

B. Inferior

C. Dorsal

D. Anterior

E. Both A and D

F. Both B and C

F) both B and C

• Inferior and dorsal

Biological hierarchy

Respiratory system (Earthworm, rat, isopod) chart

earthworm organ (respiratory system)

earthworm movement of gases (respiratory system)

CO2 in capillaries —> across skin epithelial —> into the atmosphere (down concentration gradient); O2 moves from air to mucous on skin —> crosses skin into capillaries

Earthworm O2 carrying protein (respiratory system)

iron containing hemoglobin called erythrocruorin

rat organs (respiratory system)

mouth, nose, trachea, lungs, and diaphragm

rat movement of gases (respiratory system)

pressure gradient —> air movement into the nose/mouth —> trachea —>

bronchi —> bronchioles —> into alveoli partial pressure differences —> CO2 moves from pulmonary capillaries into alveolar air; O2 moves from alveolar air into pulmonary capillaries

Isopod organ (respiratory system)

pleopods (exopodites and endopodites)

pseudo tracheae (air trees or air tubes)

isopod movement of gases (respiratory system)

CO2 from the haemolymph (blood) —> air tubes —> across pleopodal surface —> to atmosphere O2 enters exopodite openings of the pleopods —> transverses the air tubes (enfolding of the exopodite tissue —> to the sinuses or open canals where the haemolymph flows —> diffusion into haemolymph

Isopod O2 carrying protein (respiratory system)

copper containing protein called hemocyanin

earthworm skin

epidermal tissue surrounded by a cuticle

• cuticle moistened by secretion from epidermal mucous glands

earthworm circulatory system (diagram)

A closed circulatory system, consisting of dorsal and ventral blood vessels and several aortic arches that pump blood throughout the body.

rat respiratory system (diagram)

The rat respiratory system includes the trachea, bronchi, and lung

• facilitating gas exchange by delivering oxygen and removing carbon dioxide.

rat circulation (digram)

The rat circulatory system consists of a closed system featuring a four-chambered heart, arteries, veins, and capillaries that transport blood throughout the body.

ispod lungs (diagram)

The ispod lungs function in gas exchange, providing oxygen to the bloodstream and removing carbon dioxide.

earthworms move in a

wavelike motion via peristalsis due to contraction and relaxation of muscles in their body wall

earthworms have

circular and longitudinal muscles that facilitate crawling, burrowing and achoring

arthropods, annelids, and chordates are universally considered

segmented

Annelids bodies are segmented called

metamerism

earthworms are

bilaterally symmetrical, triblastic organisms with organ systems in a true coelomate body plan

earthworm adaptations enable them to

live and reproduce on land, a contrast with their relatives like marine, freshwater, and parasitic annelids as well as mollusks

earthworm diagram

rodent - clear away the connective tissue in the throat region and you see the

thymus and thyroid glands

thymus gland

large, can be found in throat region and thoracic cavity, surrounding the heart

• grainy texture which differentiates it from the connective tissue

thyroid (rat)

small, dark, symmetrical organ in midline of rat’s neck

trachea

• dorsal to thyroid

• ringed catilage prevents collapse of the trachea during inspiration

larynx is

anterior to the trachea

esophagus is

dorsal to the trachea

jugular veins

large vessels near the surface of the neck

jugular veins, carotid arteries, and vagi are all

bilateral structures

tissues throughout the body

metabolize glucose and oxygen (O2) and produce carbon dioxide (CO2) as waste

large, multicellular organisms require a

cardiovascular system which delivers O2 and glucose to the tissues via arteries and removes CO2 via veins

• highly metabolic tissues (muscles and nervous tissue) are highly vascularized

Rat thoracic cavity diagram

after ingestion the GI tract must

digest macromolecules, absorb nutrients, and egest (eliminate unused food)

GI tract is a

long assembly line of processes that normally involve the secretion of special enzymes by glands such as the salivary glands, stomach, pancreas, etc.

GI tract begins in the ___ and ends at the ____

mouth and anus

all materials absorbed from food and liquid must

pass through the wall of the tract to enter the body

food in the mammalian tract is digested

mechanically and chemically

chewing by teeth in mouth is purely

mechanical and breaks the food into smaller particles, which increase the surface area on which digestive enzymes can act

as the bolus passes through the

pharynx, the epiglottis folds over the trachea so that the bolus can pass into the esophagus

food moves caudally within the

esophagus into the stomach

esophagus passes through the diaphragm and is found in both the

in both the thoracic and abdominal cavities

liver in rat must be

lifted in order to see the stomach

spleen

dark purple organ in the region on the left side of the stomach (when stomach is lifted up)

the stomach has a

muscular wall and contraction of this wall mixes the food and enzymes

Epithelial cells in the stomach

secrete HCl which lowers the pH (acid) of the stomach contents

HCl stimulates

release of pepsinogen, a zymogen (inactive proenzyme) that is converted to the active enzyme, pepsin

pepsin is a

protease that digests protein

stomache empties into the first section of the

small intestine called the duodenum

pancreas is in the

bend of the duodenum caudal to the stomach

small intestine

where majority of the nutrient and water absorption takes place

• lining has a long of folds

folds increase

surface area for greater food absorption

intestine are surrounded by

mesentery

mesentery is a

two layered membrane of mesothelium and connective tissue that supports the blood vessels, lymphatic vessels, and nervous tissue of the intestines

diagram of rat abdominal cavity

kidney are the

primary organ and they filter the blood to form urine

ovaries in female are

small kidney shaped organs withing the abdominal cavity just caudal to the kidney

horn of the uterus are

equivalent to fallopian tubes in humans

• join centrally at the uterus

down the uterus is the

vagina (must cut the ventral pubic bone) where it joins the urethra and exits the body

in males the scrotal sacs are on the

exteriori

in order to find the testes

locate the two ductus deferens: tubes which join dorsally to the caudal end of the bladder which can be traced to the abdominal wall

dissection strategy outline

• research organism

• work slow

• examine external structure

• document

• dissect superficially

• gently separate tissues and identify structures

• determine function of structures

• make connections between systems

blunt edged tools

used before the pointed tools as they are more forgiving and less likely to cut tissue

use scissoes

more control over cut

• scalpel only when needed, for clean straight incision in skin

most organs are easier to see when

immersed in water

inflate organs

immerse in solution to make organs float to improve identification of small, cardiovascular structure

forceps

grasp parts for cutting or pill things out of the way such as with initial incisions of the skin

dissecting needle

used to tear connective tissue to separate organs one from another

blunt probe

allows you to move or hold organs and tissues out of the way without worrying about ripping or tearing them

• allows you to probe organs in the regions of an animal without destroying organs, it allows you to explore inside of hollow organs

scissors

allows you to cut through organs or cut out organs for removal to gain access to another organ

• cut through skin and make specific incisions

cutter

allows you to cut through bone or thick muscle (not to be used on earthworm)

dissected earthworm (diagram)

rat incession lines

rat dissection labeled

Which spatial planes would you use to dissect a mouse if you want to produce 1) a dorsal and ventral half of the mouse? 2) a right and left half of the mouse?

A) 1) frontal ; 2) transverse

B) 1) sagittal; 2) frontal

C) 1) transverse; 2) sagittal

D) 1) sagittal; 2) transverse

E) 1) frontal; 2) sagittal

E) 1) frontal; 2) sagittal

The kidney is _______ to most of the small and large intestine in the rat (see image).

A) dorsal

B) ventral

C) cranial

D) anterior

E) rostral

B) rostral

which of the following is correct

A) Earthworms, rats, and mice are mammals and belong to the Phylum Chordata.

B) Circulatory systems usually function to transport materials throughout the animal body.

C) Earthworms are not hermaphroditic.

D) Although isopods are technically vertebrates, rodents are considered a higher form of vertebrate.

E) Excretory systems are usually involved in gas exchange for O₂ and CO₂.

B) Circulatory systems usually function to transport materials throughout the animal body.