exothermic reaction or endothermic reaction
Saturday, September 27, 2025
sympathetic nervous system
division of autonomic nervous system that control fight or flight response
Sympathetic Nervous System
Sympathetic nervous system fight or flight response
Rest and digest response
Axon is extension of neuron sent electrical signals to the other neuron muscles and glands.
Efferent neurons
Name the two type of efferent neurons
1.Somatic division of pns control the skeletal system
2. Autonomic nervous system
Efferent neurons
Efferent neuron are motors neuron carry the signal away from thr Central nervous systems.
Afferent neurons are sensory neurons
Afferent neurons are sensory neurons carrying signal towars the Central nervous system
Wednesday, September 24, 2025
Meiosis
Quick Summary Memory Aid:
- Prophase I arrest = Before birth
- Finish meiosis I = Just before ovulation
- Metaphase II arrest = At ovulation
- Finish meiosis II = Only if fertilized
corpus albicans
if fertilization does not occur the corpus luteum becomes a
(a) Mature (Graafian) follicle
(b) secondary oocyte
(c) corpus albicans
(d) Primordial follicle
The corpus albicans is the final stage of the corpus luteum if pregnancy does not occur.
Here’s a simple breakdown:
-
After ovulation – The follicle turns into the corpus luteum, which secretes progesterone and estrogen.
-
If no pregnancy – The uterus releases prostaglandin F2α, which causes the corpus luteum to degenerate.
-
Corpus albicans – The dead corpus luteum is replaced by fibrous scar tissue called the corpus albicans (literally means “white body”).
-
Outcome – It has no hormonal activity. Over time, it shrinks and disappears from the ovary.
👉 If pregnancy does occur, hCG from the embryo keeps the corpus luteum alive, so it does not become a corpus albicans until later.
Mitosis
Mitosis involves a single cell division and result in two diploid cells
Meiosis
-
Divisions: 2 (Meiosis I and Meiosis II)
-
Result: 4 daughter cells
-
Chromosome number: Haploid (2n → n, half the parent’s number)
-
Genetic variation: Yes, because of crossing over (in Prophase I) and independent assortment.
-
Purpose: Produce gametes (sperm and eggs) for sexual reproduction
completion of meiosis produced four diploid daughter cell
DNA replication occurs in both meiosis and mitosis
DNA replications occur prior to both meiosis and mitosis
Tuesday, September 23, 2025
oocyte - Meiosis I
A mature oocyte (egg cell) does not complete meiosis right after ovulation. Here’s the timeline in simple steps:
-
Before birth – Primary oocytes begin meiosis I but stop in prophase I (they stay paused for years).
-
At puberty – Each menstrual cycle, under FSH and LH signals, some primary oocytes continue meiosis I.
-
One usually completes meiosis I just before ovulation → producing a secondary oocyte + a small first polar body.
-
-
At ovulation – The secondary oocyte starts meiosis II but stops again in metaphase II.
-
Completion of meiosis II – This only happens after fertilization by a sperm. Then, the oocyte quickly finishes meiosis II, producing a mature ovum and a second polar body.
👉 So to answer clearly:
-
A mature oocyte completes meiosis I just before ovulation, not after.
-
It only completes meiosis II after fertilization.
Progesterone Hormone
Decreasing level of progesterone lead to sloughing or shedding of the endometrium lining.
Decreasing level of progesterone lead to sloughing or shedding of the endometrium lining
Decreasing Level of Progesterone lead to sloughing or shedding of the endometrium lining
Decreasing level of progesterone level lead to sloughing or shedding of the endometrium lining
Gonadotrophic hormone released by the
Gonadotrophic hormone released by the
Anterior pituitary gland
Meiosis
During meiosis, homologous pairs of chromosomes can exchange pieces of DNA after they synapse.
https://slidetodoc.com/ch-10-sexual-reproduction-genetics-10-1-meiosis/
1. Synapsis
In prophase I of meiosis, homologous chromosomes
(one from mom and one from dad) line up tightly side by side.
This close pairing is called synapsis, and the structure formed is called a tetrad (4 chromatids together).
2. Crossing Over
At points called chiasmata, the non-sister chromatids exchange segments of DNA.
This swaps genes between maternal and paternal chromosomes.
3. Result
After crossing over, the chromosomes are genetically recombined.
This increases genetic diversity, which is why siblings look different even with the same parents.
https://slidetodoc.com/ch-10-sexual-reproduction-genetics-10-1-meiosis/
👉 In short: During meiosis, after homologous chromosomes synapse, they can exchange DNA through crossing over, creating new gene combinations.
Smallest to Largest muscle
- Myofilament
- sarcomere
- Myofibril
- muscle fiber
- fascicle
- whole muscle
MSM -MFW
- myofilament
- sarcomere
- myofibril
- muscle fiber
- fascicle
- whole muscle
MSMMFW
- myofilament
- sarcomere
- myofibril
- muscle fiber
- fascicle
- whole muscle
myofibril
Tightly packed filament bundles found within skeletal muscle fibers called myofibril
Tightly packed filaments bundles found within skeletal muscle fibers called myofibril.
Tightly packed filaments bundles found within skeletal muscle fibers called myofibril
Tightly packed filaments bundles found within skeletal muscle fibers called myofibril
Tightly packed filaments bundles found within skeletal muscle fibers called myofibril
Fascicle
bundle of muscle fibers is called fascicle
Bundle of muscle fibers is called fascicle
Bundle of muscle fibers is called fascicle
Bundle of muscle fibers is called fascicle
Bundle of muscle fibers is called fascicle
Myofilaments
Myofilament - Filament of myofibrils constructed from proteins , principally myosin or actin
Myofilament -Filament of myofibrils constructed from protein principally myosin and actin filaments
Myofilament filament of myofibrils constructed from protein principally from actin and myosin
Myofilaments -Filament of myofibrils constructed from protein principally from actin and myosin
Endoplasmic reticulum
Both type of cell
carries substances, like protein to various part of the cell .
- Protein synthesis ,
- lipid metabolism,
- cellular signaling
Ribosome
Ribosome - Protein synthesis
Cytoplasmic organelles at which proteins are synthesized.
Ribosomes translate messenger RNA (mRNA) into polypeptide chains, linking amino acids in the order specified by the mRNA codons, which is essential for cellular function and growth
Cytoplasmic organelles at which proteins are synthesized.
Lysosome
An organelle that contains digestive enzyme
An organelle that contains digestive enzyme
A lysosome is a small, round organelle found mainly in animal cells. It works like the cell’s recycling and cleanup center.
Mitochondria
Power house of cell production -
Question: 38 of 44
- Time Remaining: 06:23:40
Which of the following cell organelles are abundant in nerve and muscle cells to help meet their ATP requirements?
Mitochondria play a role in cellular respiration and help generate ATP, which provides cellular energy to carry out different functions.
Main function: They produce energy in the form of ATP (adenosine triphosphate) through a process called cellular respiration.
Mitochondria - Powerhouse of cell production -
mitochondria - Powerhouse of cell production -
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