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Understanding Reproductive Processes and Contraceptive Methods

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Stages of Reproduction

The formation of gametes, fertilization in order to form the zygote, and the development of the embryo.

Ovarian Cycle

Oogenesis occurs regularly in women from puberty onwards, every 28 days, and takes place in 3 stages:

Follicular Phase

Lasts 14 days.

Ovulation

Consists of the release of an ovum through the ovary as a consequence of the production of the hormone LH by the hypophysis.

Secretory Phase

Once the ovum is released, the corresponding area transforms into a mass of cells that produces and secretes the hormone progesterone.

Fertilization

Takes place inside the female reproductive system, usually in the fallopian tubes. Every ejaculation expels more than 300 million sperm, but only one of them will fertilize the ovum. When
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Understanding the Cell Cycle and Plant Anatomy

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The Cell Cycle

The cell cycle consists of two main phases: interphase and mitosis (M phase) [3].

Interphase

Interphase is further divided into three phases:

  1. G1 phase (Gap 1): During this phase, the cell grows in size and carries out normal metabolic activities [4].
  2. S phase (Synthesis): In this phase, DNA replication and chromosome duplication occur [4].
  3. G2 phase (Gap 2): The cell continues to grow and prepares for cell division [4].

Mitosis (M phase)

Mitosis is the actual phase of cell division and is divided into four stages:

  1. Prophase: Chromosomes condense, the nuclear envelope and nucleolus disappear, and spindle fibers start to appear [4].
  2. Metaphase: Chromosomes align at the equatorial plate [4].
  3. Anaphase: Centromeres divide, and chromatids move towards
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Sensory and Motor Responses in the Nervous System

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Stimulus occurs / Sensory Receptors Detect the Stimulus / Sensory Neurons Receive the Information and Transmit It to the CNS / CNS Receives the Information and a Response is Decided / Motor Neurons Transmit the Response to the Effectors / Effectors Carry Out the Response / A Response is Given (Motor or Secretory Response)

Light Rays, Reflected off Objects, Pass Through the Cornea, the Aqueous Humour, the Pupil, and Then Reach the Lens. The Lens Changes the Shape to Focus Objects at Different Distances (Accommodation). In the Retina, the Image is Inverted. Photoreceptors in the Retina Convert the Image into Nerve Impulses, Which Are Carried by the Optic Nerve to the Cerebral Cortex.

Myopia: Eyeball is Too Long, Images are Focused in Front of the

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Coh3 chemical name

Posted by aakankshajayant and classified in Biology

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In a hydrocarbon chain, one or more hydrogens can be replaced by these elements, such that the valency of carbon remains satisfied. In such compounds, the element replacing hydrogen is referred to as a heteroatom. These heteroatoms confer specific properties to the compound, regardless of the length and nature of the carbon chain and hence are called functional groups.•such a series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series.•The names of compounds in a homologous series are based on the name of the basic carbon chain modified by a “prefix” “phrase before” or “suffix” “phrase after” indicating the nature of the functional group. C + O2 → CO2
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Explaining Diversity of Living Things: Fixism, Evolution, and Ecological Factors

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How does Fixism explain the diversity of living things?

(4 marks) Fixism claims that species were created the way they are now, given that they do not change. Therefore, the diversity we find today is the diversity that has always existed. c.

Explain why two very different species such as birds and butterflies can have similar wings, responsible for the same function. Which evidence of evolution is it? (4 marks)

Given that both species must adapt to the same environment, they end up developing similar structures. It is an example of convergent evolution.

According to Darwin, why do individuals compete against each other? What are the consequences of this constant competition? (4 marks)

The cause is the lack of resources in an environment and the... Continue reading "Explaining Diversity of Living Things: Fixism, Evolution, and Ecological Factors" »

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The Nervous and Endocrine Systems: A Comprehensive Overview

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The Nervous System

Cranial Nerves

Twelve pairs of cranial nerves enter and exit the brain, comprising sensory, motor, and mixed types. They innervate the head, upper torso, and some internal organs. Some cranial nerves are associated with the autonomic nervous system. Along their pathways, ganglia—groups of neuronal cell bodies—can be observed.

Spinal Nerves

Thirty-one pairs of mixed spinal nerves emerge from the spinal cord. Each nerve originates as two distinct roots—dorsal and ventral—which merge to form a single nerve cord. Sensory neurons enter the spinal cord through the dorsal root, while motor neurons exit through the ventral root.

The Autonomic Nervous System

The autonomic nervous system (ANS) regulates involuntary bodily functions.... Continue reading "The Nervous and Endocrine Systems: A Comprehensive Overview" »

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Central and Peripheral Nervous System: Functions and Coordination

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Central Nervous System (CNS)

The CNS receives information from all over the body. It interprets this information and uses it to control the body's systems. The CNS consists of the brain and the spinal cord. The brain and the spinal cord are surrounded by three membranes called meninges. The CNS is mostly made up of two types of tissue:

  • Grey matter: This is mainly neuron cell bodies and dendrites.
  • White matter: This is mainly nerves. These are long cables containing axons, covered in a substance called myelin.

Brain

The brain is the control center of the body and has several key parts:

  • Cerebrum

    The cerebrum interprets information from the sense organs. It also controls language, memory, and thought. It produces voluntary responses, which are responses

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Formation of urine

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Special diets:

-Low cholesterol diet

-Low salt diet

-Gluten free diet

-Diabetes diet

-High or low calorie diets

Excretion:Is the process of

eliminating or expelling waste

matter from our bodys.

Excretion of CO2: Carbon

dioxide is produced during

cellular respiration and is

excreted from the body by

the lungs.

Wastes that are solids:The urine

and the sweat.

The urine:This is usually yellow

or transparent , but it can be

opaque when there is a lot of

waste. More or less the 95% is

water and the other 5% are

dissolved substances .The

composition is similar to blood

plasma .Urea is the primary

waste molecule in the urine .

Sweat:Is similar to urine but is

more dilute , approximately 99%

water.

sweat glands.The tiny , tubular

structures within the skin expel

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Human Health and Disease Prevention

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Human Beings and Health

The World Health Organisation (WHO) defines health as 'the complete physical, mental and social well-being, not only the absence of disease'.

Factors that Influence Health

The environment: healthy surroundings should be free of biological, physical or chemical elements that are harmful to your health.
Personal characteristics: genetic factors, age and gender predispose people to suffer from certain types of illnesses.
Lifestyle: healthy habits and lifestyles are very important for staying healthy.
Healthcare: it is essential to have an efficient healthcare system to guarantee public health.

Vital Signs

Vital signs are physiological parameters that inform us of our state of health or the evolution of a disease.

Body temperatureHeart
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Understanding the Brain: White Matter, Parts, and Functions

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White Matter:

Formed by neurons' axons, white matter acts as communication cables and the connection between control centers.

Brain:

Part of the central nervous system found within the cranium, the brain weighs 1.4kg and is the largest organ in our body. It serves as the center of integration and consciousness. The brain is organized with grey matter making up the outer surface and white matter in the interior. Cranial nerves emerge directly from the brain, which is part of the peripheral nervous system.

Parts of the Brain:

  • Cerebellum:

    The largest part of the brain, consisting of hemispheres, the corpus callosum, the hippocampus, the thalamus, and the hypothalamus.

  • Hypothalamus:

    The master gland of the endocrine system, controlling most of its activity.
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