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Frog dissection Biology 1110 Frog dissection Biology 1110

Frog dissection Biology 1110 - PowerPoint Presentation

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Frog dissection Biology 1110 - PPT Presentation

Lab 5 ReviewSupport Material Frog Dissection This presentation is not intended to replace the dissection lab exercise The purpose is to assist you if you are dissecting on your own or to help review your understanding and prepare for the lab practical ID: 918365

frog cavity heart dissection cavity frog dissection heart bladder body liver nerve abdominal pictures bile stomach skin tissue mesentery

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Slide1

Frog dissection

Biology 1110Lab # 5 – Review/Support Material

Slide2

Frog Dissection

This presentation is not intended to replace the dissection lab exercise.

The purpose is to assist you if you are dissecting on your own, or to help review your understanding, and prepare for the lab practical.

Slide3

Anatomical Requirements of the Dissection

The dissection will emphasize the general anatomy of this vertebrate.

The 26 required items are seen in the diagram and listed in the next slides.

Although there will be some discussion regarding the physiology (function) of observed structures, physiology is not intended to be emphasized in this exercise.

Slide4

Dissection Requirements

Slide5

Dissection Requirements

Slide6

Frog Dissection

Equipment required.

Preserved frog

Slide7

Opening the body cavity for observation

This diagram demonstrates the cuts that are to be made in order to open the body cavity.

The cuts are made twice, first through the skin and then through the entire body wall.

Slide8

Frog Dissection

The initial cuts are illustrated on this frog.

When making any cuts an upward pressure prevents damage to underlying structures.

Slide9

The first cuts through the skin have been made and the skin has been pinned back.

A close look at the skin reveals the significant vasculature (blood vessels) in the skin.

The frog exchanges respiratory gases utilizing a pair of lungs and the moist skin.

Slide10

The second cuts are made through the abdominal wall and thoracic (chest) wall.

The final cuts required to open the body cavity are animated.

Slide11

The body cavities have been successfully opened.

You are now ready to begin your observations.Two dissected frogs will be used to complete the dissection requirements.

Slide12

Dissection Requirements.

By clicking the forward ( ) and backward ( ) button you can jump from this requirement list to the appropriate picture(s) and then back to the list. We will not cover the requirements in the order previously presented.

Liver – the largest organ in the abdominal cavity.

Heart and surrounding pericardium.

Lungs – a pair located in the thoracic (chest) cavity

Brachial nerve – a large nerve servicing the upper

extremities.

Slide13

Gall Bladder and bile duct – check under the liver.

Stomach – In the abdominal cavity; C-shaped.

Pancreas –

small strap of tissue within the stomach’s “C”

Intestine –

trace from the stomach; small and large portion.

Peritoneum - the lining of the body cavity

Mesentery -

abdominal tissue supporting numerous organs.

Spleen – lymphatic tissue found within the mesentery.

Slide14

Kidneys - a pair of organs within the abdominal cavity.

Testes – primary sex organs of the male

Ovary – primary sex organ of the female

Oviduct – delivers the egg cell to the external environment.

Urinary Bladder – stores the urine produced by the kidneys.

Skeletal muscle - contraction moves the skeleton

Tendon/tendon of Achilles – tendons attach muscle to bone.

Long bone (femur) cut to demonstrate marrow cavity

Sciatic nerve - the largest nerve in the body.

Slide15

Liver

The liver is a large, multi-lobed organ found within the abdominal cavity. In addition to being a major detoxifying organ, the liver produces most of the plasma proteins, & stores valuable commodities. The liver also produces the bile that is stored in the gall bladder, and used in the digestion of fats.

Slide16

Heart and Pericardium

The amphibian heart is a three-chambered heart. Your heart has four chambers. The heart resides within the pericardium, a sac-like structure that contains lubricating pericardial fluid.

Both pictures clearly demonstrate the heart and pericardium. The forceps in the right picture is holding the tissue of the pericardium.

Slide17

Heart and Pericardium

Additional pictures of a frog heart residing within the thoracic (chest) cavity, and contained within the pericardium.

Slide18

Right and Left Lung

Head

Head

The pair of lungs is also located deep within the thoracic cavity. Amphibian lungs are rather sac-like with much less surface area than mammalian lungs. As a consequence the amphibian lung is not as efficient.

Gas exchange through the skin helps make up for this inefficiency. It also explains why almost all amphibians must keep their skin moist.

Slide19

Brachial Nerve

A brachial nerve can be seen entering each of the frog’s forelimbs. The brachium is the upper area of each limb.

Slide20

Gall Bladder and Bile Duct

Liver lobe

Head

Head

In both pictures the liver has been reflected back so as to reveal the somewhat spherical, green gall bladder. The gall bladder stores the bile produced by the liver. The bile is then delivered via the bile duct to the small intestine. Bile functions in the digestion of fats.

Slide21

Stomach

The stomach is a food storage organ and is involved in the digestion of proteins. When stomach processing is complete the material is released into the small intestine.

Stomach

Head

Slide22

Pancreas

The pancreas produces a variety of digestive enzymes that are delivered into the small intestine.

The pancreas also produces a couple of hormones involved in sugar metabolism. One of the hormones is insulin.

In the frog, the pancreas is a thin tissue strap located within the “curve” of the stomach.

Slide23

Intestinal Tract

The small intestine is of considerable length and is involved in the digestion of food and absorption of nutrients.

The larger portion of the intestinal tract is identified by the probe in the picture on the right.

Intestinal tract

Slide24

Peritoneum

The peritoneum is the smooth, moist lining of the body cavity. It composed of simple

squamous

epithelium (studied earlier).

Peritoneum

Slide25

Mesentery

The mesentery is made of the same tissue, and is connected to the peritoneum. The mesentery is a double layer of this tissue and invests many abdominal organs as seen in both pictures.

Lifting the digestive tract reveals the extensive nature of the mesentery. This tissue has numerous functions.

Slide26

Spleen

When the digestive tract is lifted, and the mesentery demonstrated, a structure within the mesentery becomes obvious.

The spleen is pointed out in both pictures.

The spleen is part of the lymphatic system. One important function is in the breakdown and recycling of worn out red blood cells.

Slide27

Kidneys

The pair of kidneys, in the process of urine formation, remove waste products, help maintain acid-base balance, electrolyte balance and water balance.

The kidneys are located against the back body wall in the abdominal cavity. In the pictures below they are the brown structures identified.

Left kidney

Right kidney

Slide28

Gonads – male testes

The primary sex organ of this male frog are the testes. The right testicle is pointed out in both pictures. The testes produce the male gametes (sperm cells) that will fertilize the female egg cells.

You can see their location close to the kidneys.

Right testicle

Slide29

Gonads – female ovary and oviduct

The female frog in the picture below demonstrates a condition

of reproductive inactivity. The ovary is the primary sex organ,

and produces the gametes (egg cells). The oviduct is also

demonstrated.

Ovary

Oviduct

Slide30

Urinary Bladder

The urinary bladder stores the urine produced by the kidney.

In the picture the forceps is demonstrating the urinary bladder.

Slide31

Skeletal (Striated) muscle and Tendon

The frog’s right leg has been skinned in order to demonstrate the large swimming and jumping muscles of the leg.

Tendons attach skeletal muscles to the bones of the skeleton. When the muscle contracts the force is transferred through the tendon to the bone, causing movement.

Tendon of Achilles is demonstrated

Slide32

Cross-section of long bone (femur) demonstrating marrow cavity.

In the pictures we see that the femur has been cut. The picture on the right demonstrates the presence of the marrow cavity within the bone.

Slide33

Sciatic Nerve

The largest nerve in your body is the sciatic nerve that services the lower extremities. It is demonstrated in both photographs.

Click arrow to continue to the frog model

Slide34

Frog Model

The next couple of slides will review certain frog structures previously seen in the dissection.

Slide35

Frog Model

Heart

Lung

Gall Bladder

Large Blood Vessels Above Heart

Liver

Slide36

Frog Model

Bile Duct

Egg mass

Oviduct

Kidneys

Stomach

Spleen

Intestine

Urinary Bladder

Pancreas

Slide37

The End