শিক্ষামূলক নোট: এই পৃষ্ঠা একাডেমিক জীববিজ্ঞান শেখা ও পরীক্ষার প্রস্তুতির সহায়ক।
Temporary Mounting
General Rule
Temporary mount-এ structure intact, moist এবং minimally distorted রাখতে হবে। Coverslip pressure সবচেয়ে common source of error।
1. Brain of Earthworm
Aim
Cerebral ganglia এবং circumpharyngeal connectives demonstrate করা।
Procedure logic
- Anterior few segments isolate/secure করো।
- Dorsal body wall open করে pharyngeal region expose।
- Pharynx-এর dorsal side-এ paired cerebral ganglia locate।
- Fine needle দিয়ে surrounding connective tissue remove।
- Circumpharyngeal connectives যতটা সম্ভব preserve করে brain isolate।
- Saline/glycerin-based temporary medium-এ transfer।
- Coverslip gently lower; crush করবে না।
Identify
- paired cerebral ganglia;
- commissural connection;
- circumpharyngeal connectives.
Identification
Paired supra-pharyngeal cerebral ganglia ও circumpharyngeal connectives থাকার কারণে preparation-টি earthworm brain।
2. Salivary Gland of Cockroach
Aim
Paired salivary glands, reservoirs and ducts demonstrate করা।
Procedure logic
- Specimen ventral/dorsal access departmental method অনুযায়ী open করো।
- Crop region-এর পাশে whitish lobulated salivary tissue identify।
- Paired glands এবং transparent reservoirs trace।
- Fine forceps/needles দিয়ে gland-reservoir unit detach।
- Saline-এ wash।
- Slide-এ spread করে coverslip gently apply।
Identify
- glandular lobules/acini;
- salivary reservoirs;
- ducts.
Common error
Fat body-কে salivary gland ধরে নেওয়া। Salivary gland more organized lobulated network; reservoir thin-walled sac।
3. Statocyst of Prawn
Aim
Antennular statocyst and statolith demonstrate করা।
Location
Statocyst usually antennule-এর basal segment (precoxa / basal podomere region) associated cavity।
Procedure logic
- Antennule detach করো।
- Basal segment isolate।
- Fine needles দিয়ে wall carefully open।
- Statocyst cavity expose।
- Sensory setae এবং sand-grain/statolith material disturb না করে mount।
- Low power-এ cavity and internal material observe।
Identify
- statocyst wall;
- sensory setae;
- statolith/sand particles where retained.
Functional interpretation
Statocyst equilibrium/orientation sense-এ সাহায্য করে। Molting-এর পরে many prawns external particles ব্যবহার করে statolith পুনর্গঠন করতে পারে।
7-mark Temporary Mount Checklist
A high-quality preparation should show:
- correct specimen/organ selected;
- minimal tearing;
- correct orientation;
- mount not too thick;
- no major air bubble over target;
- diagnostic structures visible;
- drawing properly labelled.