ZOO502 Final Term Solved Papers by Kashif Ashfaq

ZOO-502 · Animal Physiology and Behavior · Solved Repeated Questions 2018 · Virtualian Zoologists

Mcqs: The human ear can detect sound frequencies lying between 20 to 20000 hertz. In small diameter, nonmyelinated fibers, speedmay be as low as 0.25m/s. Acclimatization Happens due to chronic exposure to new, naturally occurring environmental conditions. hyperthyroidism leads to: high body temp, profuse sweating, weight loss, Irritability high blood pressure. Zoo 502

Differentiate between Norepinephrine and Epinephrine?2

Norepinephrine is the primary excitatory transmitter in postganglionic cells of sympathetic system. Epinephrine is excitatory at some synapses and inhibitory at others depending on postsynaptic membrane

2 basic types of stimuli 2 marks

• External stimuli

Stimuli of odor, touch, light, sound and gravitation

• Internal stimuli

Stimuli of pain, homeostatic imbalances and blood pressure

Define vestibular apparatus?

Vestibular apparatus, located in the inner ear. It has: Saccule Utricle Semicircular canals

Name two components of rhdopsin? 2mks

A rhodopsin molecule consists of two major components: Opsin protein A light-absorbing molecule (retinal or 3dehydroretinal) Function of LH in male and female. In Females LH stimulates production of estrogen and progesterone by ovary. It causes ovulation and formation of corpus luteum. In males, LH is also called as ICSH (interstitial cell stimulating hormone) It stimulates testosterone production by the Leydig cells of testes.

What are gonadostropin

Gonadotropins: Luteinizing and Follicle Stimulating Hormones. Luteinizinghormone (LH) and follicle-stimulating hormone (FSH) are called gonadotropinsbecause stimulate the gonads - in males, the testes, and in females, the ovaries.

Define the terms gland and secretion? 2mks

A gland is a cell or group of cells that secretes a particular chemical substance for use in the body or for discharge into the surroundings. Secretions are chemical substances, synthesized by glandular cells. They are released from the gland in response to an appropriate stimulus.

Write the role of Fibers of Zonula and ciliary muscles in eye? 3

Fibers of zonula held the lens in place. They change the shape of lens by exerting an outward tension on perimeter. Attached with fibers of zonula are the ciliary muscles They contract to pull fibers of zonula, which flatten the lens. This focuses distant objects on retina. When they relax, lens becomes rounded and near object is focused.

Describe Hodgkin cycle in detail? 3

A stimulus causes local depolarization of the membrane. Na+ channels open in response to initial depolarization. This increases Na+ conductance that allows Na+ to enter the cell, which cause further depolarization of membrane and decrease in Vm. This relationship between Na+ conductance (gNa) and Vm represents a type of positive feedback system and is termed as the Hodgkin cycle. It results in triggering of an action potential.

Which hormones are involved in the regulation of water and ions? 3

These hormones include:

•  Antidiuretic hormone (ADH)
•  Aldosterone
•  Atrial natriuretic Hormone
•  Calcitonin
•  Parathormone

Explain two types of feedback mechanism in detail? 5

Feedback controls regulate particular variables e.g., Temperature • Salinity • pH This regulation requires: Continuous sampling of controlled variables Respective corrective actions. Types of Feedback Systems Two Types:

1. Negative feedback systems
2. Positive feedback systems

Negative Feedback Systems

The most common form of regulation, The end product works to stop or slow down the process Example-1 Breakdown of sugar in the cells generates ATP, Excess ATP "feeds back" and inhibits an enzyme near the beginning of pathway. ATP production stops. Example-2 Control of blood sugar (glucose) by insulin; Receptors sense a rise in blood sugar. Control center (pancreas) secretes insulin and Insulin lowers blood sugar levels. As blood sugar level reaches homeostasis, pancreas stops releasing insulin.

Positive Feedback Systems

An end product speeds up the process of its production. Examples

1. Clotting of blood in response to an injury
2. Release of Oxytocin during labor

Enlist five functions of estrogen hormones in pregnancy? 5

•  During pregnancy, estrogens exert mainly a proliferative function on reproductive and associated organs of the mother.

They cause:

•  enlargement of uterus
•  Enlargement of breasts and growth of breast ductal structure
•  Enlargement of external genitalia
•  Relaxation of pelvic ligaments to make pubic symphysis elastic for easy passage of the fetus through birth canal

Abnormalities due to GH?5

Disturbances in the secretion of GH lead to abnormal growth and development in humans:

Gigantism

Hypersecretion of GH before puberty causes excessive size and stature.

Acromegaly

Hypersecretion of GH after maturity causes enlargement of bones of the head and limbs.

Dwarfism

Insufficient secretion of GH during childhood and adolescence causes underdevelopment of the body (short stature).