Glands & Genetics Flashcards
1
Q
Explain how endocrine and exocrine glands are classified
A
- Glands are aggregations of cells which are designed to produce secretions (2 types: exocrine & endocrine)
- Exocrine glands secrete onto epithelial surface
- They develop from epithelia (epithelial calls invaginate into underlying connective tissue to form glands)
- 3 types of secretion mechanism: Merocrine = salivary gland; Apocrine = mammary gland; Holocrine = sebaceous gland
- Also classified based on secretion type: Serous = parotid salivary gland ; Mucous = sublingual; Mixed = submandibular
- Classified based on no. of cells: Single cell → goblet cells (fallopian tube)
Multicellular → Duct = simple/compound
→ Secretory part = single/branched
→ Shape of secretory part = tubular/acinar - Simple glands classified:
→ simple tubular = fundus of stomach, glands of colon
→ simple branched tubular = pylorus of stomach
→ simple coiled tubular = sweat glands
→ simple acinar = penile urethra
→ simple branched acinar = sebaceous glands - Compound glands classified:
→ compound branched tubular = brunner’s glands
→ compound acinar = pancreas
→ compound tubuloacinar = prostate - Endocrine gland characteristics include: dense blood supply, ductless, cells organized as cords
2
Q
Monozygotic vs. Dizygotic twins
A
- Monozygotic:
→ Identical
→ Same sex
→ 1 ova fertilized by 1 sperm - Dizygotic:
→ non-identical
→ different/same sex
→ 2 ova fertilized by 2 sperms
3
Q
What are the different Extra embryonic tissue arrangements?
A
- Separation @ 2 cell stage: 2 placenta, 2 amniotic cavities, 2 chorionic cavities
- Separation @ early blastocyst stage: 1 placenta, 2 amniotic cavities, 1 chorionic cavity
- Separation @ bilaminar germ disc stage: 1 placenta, 1 amniotic cavity, 1 chorionic cavity
*Complications with separation of zygote:
1. Placental previa
2. Twin to twin transfusion syndrome
3. Conjoined twins
4
Q
Basis of autosomal dominant disorders
A
- Mutation in any chromosome except sex chromosomes
- One dominant gene is enough to express the disorder
- Vertical inheritance can be seen
- Females + males are equally affected
- Homozygous recessive does not show the disorder
5
Q
Sex chromosome anomalies
A
- Klinefelter syndrome (XXY)
→ long arms + legs, no facial hair, ↓testis
→ in males - Turner’s syndrome (X)
→ short stature, low hairline, web neck
→ in females
6
Q
Suspicious features at a neonatal exam
A
- Small head; low set ears & abnormally rotated
- Plagiocephaly
- Hyperteiorysm
7
Q
Reasons for autosomal recessive
A
- Both sexes equally affected
- Presence of skipping generations
8
Q
Reasons for X-linked dominant
A
- Affected females have 50% chance of transmitting disease to sons and daughters
- Affected males do not transmit to sons, but to all daughters
- More males affected than females
9
Q
Importance of meiosis division
A
- Produces four cells with half number of chromosomes of parent cell
- ↑ genetic diversity, ↑ amount of variation within species
- Variations improve chance of species to adapt to environment + survive
10
Q
The Cell Cycle
A
11
Q
Fertilization
A
- Fusion of male and female pro nuclei to form zygote
- Penetration of corona radiata by sperm
- Penetration of zona pellucida by sperm
- Fusion of pro nuclei
- Results in commencement of mitotic division
- Is possible to be performed in-vitro
- Ampullary region of fallopian tube is the most common site of fertilization
- POST wall of upper uterine segment is the site of implantation
12
Q
Cells & Organelles
A
- Nucleus communicates with cytoplasm through nuclear pores
- Nuclei are not present in dormant nuclei
- Ribosomes are found within mitochondria, endoplasmic reticulum & cytoplasm
- Nuclei in active cells are large and small in inactive cells
- Nuclei in active cells have more euchromatin
- Mitochondria are inherited from mother (contain DNA)
- Glycocalyx is important in cell adhesion
- Nucleolus has both DNA & RNA
13
Q
Polymorphic genes
A
- Causes variations in monogenic traits
- Does not maintain key features of species.
- Its frequency in a population determines the survival of the allele
- has a particular/fixed locus in a genome of a given species
- Phenotype is affected by environmental factors
14
Q
Nervous system
A
- White matter indicates nerve fibers
- Grey matter indicates nerve cell bodies.
- Dermatome is supplied by a single spinal nerve root.
- Sympathetic ganglia found close to spinal cord (parasympathetic are close to the organ)
- PNS → satellite cells & Schwann cells
- CNS → astrocytes, oligodendrocytes, ependymal cells, microglial cells
- Somatic sensory nerve fibers carry sensations from muscle, skin, tendon, joints
- PS system has shorter postganglionic fibers than sympathetic system
15
Q
Polygenic traits
A
- Are determined by allele on different loci
- Are qualitative traits
- Modified by environmental factors
- Contribute to variations in a population
- House keeping genes are responsible for stabilizing key features of species
