ZOO502 Practical Exam Notes

Q1. What are the four phases of the estrous cycle?

The four phases of the estrous cycle are:

1. Proestrus - follicles in the ovary start to grow, uterus lining develops.
2. Estrus - female is sexually receptive, ovulation occurs.
3. Metestrus/Diestrus - corpus luteum forms, progesterone is produced to maintain pregnancy if fertilization occurs.
4. Anestrus - sexual cycle rests, controlled by light exposure and melatonin release.

Q2. What is the purpose of using a kymograph?

The purpose of using a kymograph is to study frog heartbeat records and examine intrinsic and extrinsic factors that affect cardiac contractility and heart rate. It provides a graphical representation of the relative force and frequency of cardiac contraction over time.

Q3. What are the different locomotory organs in earthworm?

The different locomotory organs in earthworm are setae and muscle segments. Earthworms move by contracting the muscles in their segments in a wave pattern, using the setae to anchor segments and pull the body forward.

Q4. What is the estrous cycle regulated by?

The estrous cycle is regulated by the hypothalamic-pituitary-gonadal axis, which produces hormones like GnRH, FSH, LH, estrogen and progesterone to control reproductive events.

Q5. How is hemoglobin concentration determined in blood?

Hemoglobin concentration is commonly determined by the cyanmethemoglobin method in which blood is mixed with Drabkin's solution to convert all hemoglobin forms to cyanmethemoglobin. The absorbance of this solution is measured by a spectrophotometer and concentration is calculated using a standard graph or formula.

Q6. What are the effects of exercise on blood pressure?

Exercise causes an increase in systolic blood pressure to meet the oxygen demands of working muscles. Systolic pressure can rise to 160-220 mmHg during exercise in healthy individuals. Diastolic pressure may stay the same or rise slightly.

Q7. What is the function of hemoglobin?

The function of hemoglobin is to transport oxygen from the lungs to body tissues. It also transports carbon dioxide back from tissues to the lungs. Thus it facilitates gas exchange.

Q8. What are the locomotory organs in snails?

Snails move by gliding along on their muscular foot which is lubricated with mucus and covered with epithelial cilia. The mucus aids locomotion by reducing friction. The motion occurs due to waves of muscular contractions moving down the ventral surface of the foot.

Q9. What is the purpose of a Skinner box?

A Skinner box is used to study operant conditioning behaviors in animals. It contains a lever which the animal must press to receive a food reward. By observing when and how often the lever is pressed, insights are gained into learned behaviors.

Q10. What are the components measured in a blood pressure reading?

The components measured in a blood pressure reading are systolic pressure (maximum pressure when heart contracts) and diastolic pressure (minimum pressure when heart relaxes between beats). Readings are typically expressed like "120 over 80 mmHg".

Q11. What are the stages involved in RBC counting using a hemocytometer?

The stages are: sample dilution, chamber filling, microscopic observation and counting of RBCs in corner squares, and finally calculation of total RBC concentration using dimensions of the squares and dilution factor.

Q12. What is the purpose of dissolved oxygen meters in fish farms?

Dissolved oxygen meters allow frequent, rapid measurement of oxygen levels so fish farmers can monitor water quality and activate aerators when oxygen depletion occurs due to respiration by fish, plankton and pond organisms.

Q13. What are the effects of temperature on: a) Cardiac activity b) Oxygen consumption?

1. Low temperatures decrease heart rate and contractility; high temperatures increase them.
2. Warmer temperatures increase oxygen consumption rates in organisms like fish.

Q14. How does the social hierarchy in chickens establish itself?

In young chicks, the pecking order starts emerging around 16 days of age through fighting and aggressive displays like chest-bumping. In female chicks it stabilizes after 10 weeks while male groups may take longer to establish a linear order.

Q15. What are the different types of parental care in birds?

The types are: bi-parental care where both mates feed and protect chicks, and mono-parental care where one parent (usually the female) takes sole responsibility. Most bird species demonstrate bi-parental care to improve fledgling success.

Q16. What are the effects of acetylcholine on frog heartbeat?

Acetylcholine decreases both the rate and strength of frog heartbeat by interfering with pacemaker potentials and conduction in the heart.