This document provides an overview of frog anatomy and physiology. It describes several of frog's key body systems that are simpler versions of human systems, making frogs a useful model organism. The summary includes: - Frogs have simpler versions of the same major organ systems as humans, like skeleton, heart, skin, and nervous system. - Their physiology is well-understood, diverse taxonomically, and similar enough to humans to enable comparative studies. - Key anatomical features described include the flat skull, 9 vertebrae backbone, lack of ribs, single-chamber heart, thin moist skin aiding respiration, and digestive system leading from mouth to intestines to cloaca.

1. Frog
anatomy &
physiology
Ahmed Adel
MASTER OF BIOTECHNOLOGY, AUC.
GENOMICS AND BIOINFORMATICS
DIPLOMA, FACULTY OF PHARMACY,
CAIRO UNIVERSITY
BACHELOR'S DEGREE IN
BIOTECHNOLOGY, MUST.

2. Why studying frogs as a model organism?
• Their physiology is well-understood.
• Their taxonomic diversity is well suited to comparative
studies.
• They have a great similarity to humans, have the same
kinds of organs and systems. The frog’s anatomy,
however, is much simpler.

7. THE
SKELETON
AND
MUSCLES
The skull is flat, except for an expanded area that
encases the small brain.
Only nine vertebrae make up the frog’s backbone,
or vertebral column, compared to the human
backbone, which has 24 vertebrae.
The frog has no ribs.
Skeleton-moving muscles are made of skeletal, or
“striated,” muscle. Internal organs contain smooth
muscle tissue.

9. THE CIRCULATORY
SYSTEM
The frog heart is the only organ has its own
protective covering (pericardium).
There are two upper chambers of the heart, the right
atrium and the left atrium. The frog heart, however,
has only one lower chamber, a single ventricle.
In humans, the lower heart chamber is divided into
two compartments, the right ventricle and the left
ventricle.

12. THE SKIN AND RESPIRATORY SYSTEM
The frog is covered by a soft, thin, moist skin composed
of two layers.
The skin helps in respiration under the water by an
extensive network of blood vessels runs throughout the
frog’s skin.
Oxygen can pass through the membranous skin, thereby
entering directly into the blood.

16. THE
DIGESTIVE
AND
EXCRETORY
SYSTEMS
The frog’s mouth is where digestion begins.
The frog’s tongue is highly specialized. Normally,
the tip of its tongue is folded backward toward
the throat.
Food passes from the frog’s mouth into the
stomach by way of the esophagus.
From the stomach, the food moves into the small
intestine, where most of the digestion occurs.

17. THE
DIGESTIVE
AND
EXCRETORY
SYSTEMS
Large digestive glands, the liver and the
pancreas, are attached to the digestive
system by ducts. A gall bladder is also
present.
Liquid wastes from the kidneys travel by
way of the ureters to the urinary bladder.
Solid wastes from the large intestine pass
into the cloaca. Both liquid and solid waste
material leave the body by way of the
cloaca and the cloacal vent.

18. • Peritoneum: Spiderweb like
membrane that covers
organs
• Stomach: First site of
chemical digestion, breaks
down food
• Liver: Makes bile (aids in
digestion)
• Gall bladder: Stores bile
• Esophagus: Tube that leads
to the stomach
• Pancreas: Makes insulin
(aids in digestion)
• Small Intestine (duodenum,
jejunum and ileum): absorb
nutrients from food
• Large Intestine: Collects
waste, absorbs water
• Cloaca: "Sewer": eggs,
sperm, urine and feces enter
this area
• Spleen: Part of circulatory
system, stores blood

21. THE NERVOUS SYSTEM AND SENSE ORGANS
It consists of a brain, a spinal cord, and nerves.
Only 10 cranial nerves originate in the frog’s brain.
Humans have 12. Similarly, the frog has only 10 pairs of
spinal nerves. Humans have 30 pairs.

22. SENSE ORGANS
The eye has fixed lens cannot change its focus.
Poorly developed eyelids do not move.
There is no external ear. Both eardrums, or tympanic
membranes, are exposed.

23. Frog Reproductive System
Ova or Eggs - Female sex cell or gametes.
Ovaries - Organs of the female reproductive system that
produce the eggs.
•Oviducts - Tubes of a female frog’s reproductive system
that carry eggs from the ovaries to the cloaca.
•Testes - Male sex organs that produce sex cells (sperm).
•Sperm - Male sex cell or gametes.

24. References
https://kids.britannica.com/students/article/Anatomy-of-the-frog/274440
https://www.istockphoto.com/search/2/image?phrase=frog+anatomy
https://www.shutterstock.com/image-illustration/illustration-basic-frog-
anatomy-1687673737
https://www.biologycorner.com/bio2/notes-frog.html
https://academic.oup.com/ilarjournal/article/48/3/260/664101

25. Thank you