Endocrine System and Muscle Physiology: Hormones, Contraction & More
Endocrine System and Muscle Physiology
Motor Neuron Axon Terminal
- Action potential reaches axon terminal of motor neuron.
- Voltage-gated Ca2+ channels open, allowing Ca2+ to enter the motor neuron.
- Vesicles fuse with axon terminal membrane, releasing acetylcholine (ACh) into the synapse (always excitatory between motor neuron and muscle cell).
- ACh diffuses to the skeletal muscle cell membrane and binds to nicotinic acetylcholine receptors (nAChR).
- nAChR are activated, allowing ions to enter the muscle
Kingdoms of Life: Classification & Characteristics
Kingdoms of Life
Biological Classification
In biology, a kingdom is a major subdivision of living organisms, categorized based on shared characteristics. The earliest classification into kingdoms dates back to Aristotle, who distinguished between the animal, vegetable, and mineral kingdoms.
Key historical classifications include:
- Carl Linnaeus (1735): Vegetalia and Animalia
- Ernst Haeckel (1866): Protista, Plantae, Animalia
- Whittaker (1969): Monera, Protista, Fungi, Plantae, Animalia
Kingdoms are further
Read MoreThe Nervous and Endocrine Systems: Anatomy and Physiology
1. The Nervous System
The nervous system, through sensory organs, allows interaction with the external environment. It is divided anatomically into:
a) Central Nervous System (CNS)
- Brain: Telencephalon, Brainstem, Cerebellum
- Spinal Cord: White matter, Gray matter
b) Peripheral Nervous System (PNS)
- Cranial nerves
- Spinal nerves
According to their functional characteristics, they are divided into:
a) Somatic Nervous System (Voluntary)
Nerves that innervate muscles.
b) Autonomic Nervous System
- Sympathetic
- Parasympathetic
2.
Read MoreUnderstanding Environmental Factors and Adaptations
1. The Environment and Environmental Factors
The environment encompasses the conditions surrounding a place or organism. Environmental factors influence how species are distributed and determine their survival. These factors can be divided into two categories:
Abiotic Factors
These are the physical and chemical factors of the environment that can change over time and affect the survival of organisms. They include:
- Physical factors: Temperature, rainfall, light, solar radiation, humidity, latitude, altitude,
Characteristics and Formation of Living Things: A Comprehensive Guide
Characteristics of Living Things
- Complexity: Composed of numerous molecules.
- Cells: Unicellular and multicellular organisms.
- Life Functions:
- Nutrition: Obtaining matter and energy.
- Relation: Interaction with the environment.
- Reproduction: Producing offspring.
Formation of Living Things
Formed by chemical compounds similar to bioelements (e.g., carbon, hydrogen, oxygen, nitrogen) called biomolecules.
Types of Biomolecules
- Inorganic: Water and minerals (carbonates, phosphates).
- Organic: All contain carbon.
- Carbohydrates:
Introduction to Genetic Engineering
4) Cellular Structural Proteins and Nucleic Acids
Nucleic Acids
DNA is a double helix formed by the repetition of four molecules called bases: adenine, guanine, cytosine, and thymine. These bases contain nitrogen. The size of a DNA molecule is measured in bases, kilobases, or megabases. DNA is shaped like a spiral staircase. Its railings are formed by each of the two strands, with monotonous successions of the four components of the DNA alphabet: A, C, G, and T. The steps of the staircase are chemical
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