What is a hormone and how does it affect the target cell?
rubabAn animal hormone (Grhormaein, to set in motion or to spur on) is a chemical signal that is secreted into body fluids, most often into the blood, by specialized cells…
What are chemical messengers? How can we categorize them?
Chemical messengers are involved in communication in maintaining homeostasis in an animal's body, and in the body's response to various stimuli. The development of most animals commences with fertilization and…
THE ENDOCRINE SYSTEM AND CHEMICAL MESSENGERS
Introduction Hormones are chemical messengers synthesized by special endocrine and other cells and transported by the blood to target cells where they affect cell function by altering specific biochemical processes.…
Fill In The Blanks of Nervous And Sensory System
1 Name the chief structural and functional units of the nervous system._______ 2 Name the chemical signals which are slower, and initiate and widespread, prolonged response often in a variety…
OBJECTIVES OF NERVOUS AND SENSORY SYSTEMS
1- Which of the following are the integrative systems in our body? (a) nervous system (b) endocrine system (c) both of these (d) none of these 2. Nervous system in…
What is a Jackobson’s organ
Olfactory senses are better developed in reptiles than in amphibians. In addition to having more olfactory epithelium, most reptiles (except crocodilians) possess blind-ending pouches that open into the mouth These …
Write a note on taste buds
Taste buds are barrel-shaped clusters of chemoreseptor cells called gustatory cells and supporting cells arranged like alternating segments of an orange. Extending from each receptor cell are gustatory hairs that…
What is rhodopsin, and how does it functions?
What is rhodopsin, and how does it functions? Ans. Both rods and cones contain light sensitive pigments known as rhodopsins. Each rhodopsin molecule consists of a large protein, opsin, which…
What animals possess a median eye?
Vision is the dominant sense in most reptiles, and their eyes are similar to those of amphibians. Upper and lower eyelids, a nictitating membrane, and a blood sinus protect and…
Describe the structure of vertebrate eye.
All vertebrates possess complex camera eyes. A camera-type eye contains in the front a light-tight chamber and lens system, which focuses an image of the visual field on a light…