Notes, summaries, assignments, exams, and exercises for Biology for Vocational training

Trigeminal Nerve (V3) Anatomy

The trigeminal nerve (V3), also known as the mandibular nerve, has an anterior trunk (mainly motor) and a posterior trunk (sensory). It supplies taste sensory innervation to the anterior part of the dorsum of the tongue via fibers of CN7. Before dividing into two terminal trunks, there are two lateral branches:

• Meningeal branch: Sensory, supplies the dura mater of the middle cranial fossa.
• Medial pterygoid muscle nerve: Motor nerve, supplies the medial pterygoid muscle from the deep side. It also innervates the tensor veli palatini and tensor tympani muscles.

Anterior Trunk Branches

• Buccal nerve: Sensory, supplies the skin of the cheek, mucosa of the posterior and inferior portion of the vestibule, and the buccal side

Metabolism

Metabolism is the set of chemical reactions that occur inside the cell. The different sequences of reactions or routes are called metabolic pathways, and the molecules involved are metabolites.

There are two phases:

1. Catabolism: Transformation of complex organic molecules into simpler ones (degradation). This process releases energy stored in ATP's phosphate bonds.
2. Anabolism: Synthesis of complex molecules from simple ones (construction), requiring energy provided by ATP.

Structure of Metabolic Pathways

• Linear: Intermediates are only used in a particular pathway.
• Branched: Metabolic routes intersect or cross at two or more points.
• Cyclical: After a series of transformations, the initial molecule is regenerated.

Types of Metabolism Based on

Digestive Phases

Cephalic Phase

The cephalic phase initiates digestion before food even reaches the stomach. Sensory cues like taste, smell, or even the thought of food trigger the central nervous system to stimulate gastric juice production.

Gastric Phase

Once food enters the stomach, receptors signal the brain, which in turn promotes further gastric juice secretion to break down the ingested food.

Intestinal Phase

As food moves into the duodenum, receptors detect its presence and signal the brain to increase the production of digestive juices for further processing.

Enterogastric Reflex

When the duodenum is full, the enterogastric reflex is activated, causing the pyloric sphincter to close and regulate the passage of chyme from the stomach to the...

Gases, Vapors, and Associated Risks

A gas is matter neither liquid nor solid at room temperature and normal atmospheric pressure, expanding to fill any container. A vapor is the gaseous state of a substance typically solid or liquid. Fumes result from volatilization or sublimation. Gases and vapors diffuse freely, remaining mixed with air.

Lead Poisoning

Metabolism

Inhaled lead is 40-60% retained in the lungs, entering circulation. Ingested lead absorption is about 10%. Blood lead distributes to liver, kidneys, brain, and bone. Elimination occurs via respiratory tract, gastrointestinal system (bile, feces), urine, and generalized discharges (colic).

Pathological Effects

• Hematologic: Altered metabolism via enzyme changes and metabolite accumulation.

Digestive System

Main Function

The main function of the digestive system is the digestion and absorption of nutrients.

Layers of the Digestive Tract

• Mucosa: Formed by different types of epithelium depending on the zone.
• Muscularis Mucosa: Smooth muscle tissue, predominantly circular.
• Submucosa: Formed by connective tissue, blood vessels, and nerves.
• Muscularis: Formed by 2 or 3 layers of muscle tissue.
• Adventitia/Serosa: Consists of loose connective tissue or peritoneum depending on the zone.

Parts of a Tooth

• Root: Within the alveolar bone cavity.
• Crown: External, visible part of the tooth.
• Neck: Separates the root from the crown.
• Pulp Chamber: Formed by pulp, connective tissue, blood vessels, and nerves.
• Dentin: Hard tissue surrounding the pulp, covered

Real and Apparent Origins

Cranial nerves have a real origin, which is the nucleus of gray substance inside the brain, except for cranial nerves I, II, and VIII, whose real origin is outside the brain. The apparent origin is the attachment surface of the brainstem.

Specific Cranial Nerves

Olfactory Nerve (CN I)

Origin: Roof of the nasal cavity.

Optic Nerve (CN II)

Origin: Ganglionic cells of the retina.

Oculomotor Nerve (CN III)

Origin: Sulcus on the medial side of the cerebral peduncle.

• Superior division: Supplies the superior rectus and levator palpebrae superioris.
• Inferior division: Supplies the medial rectus, inferior rectus, and inferior oblique muscle.
• Function: Parasympathetic innervation, constricts the pupil via the ciliary ganglion.

Trochlear

1. Vomer Bone

Shape: Part of the postero-inferior nasal septum. Anatomical Features: Alae (wings), ridge, and furrow for choanal articulation with the vomer.

2. Sutures and Fontanelles

The bones of the cranial vault are joined by synfibrosis. We distinguish:

• Coronal suture
• Sagittal suture
• Squamous sutures
• Metopic suture
• Lambdoid suture

Schindylesis: Vomer and sphenoid crest articulation.

In newborns, skull bones are not yet firmly united at the sutures, leaving spaces called fontanelles. There are six:

• Bregmatic: Diamond-shaped, between the parietal and frontal bones.
• Lambdoid: Triangle-shaped, between the sagittal and lambdoid sutures.
• Pterygoid: Located at the junction of the frontal, parietal, temporal, and sphenoid bones.
• Asteroid: Star-shaped, between

Nucleic Acid Building Blocks

Nucleoside Structure

The nucleoside core is formed by a pentose sugar joined to a nucleobase via an N-glycosidic link. This bond occurs between carbon 1 (C1) of the pentose and nitrogen 1 (N1) of pyrimidine bases or nitrogen 9 (N9) of purine bases, with the loss of a water molecule.

Nucleotide Structure

A nucleotide is a nucleoside with one or more phosphate groups attached.

Phosphate Ester Bond

The phosphate ester bond links the C5 of the pentose sugar to a phosphate group (PO₄^3-).

Nucleotide Linkage: The Phosphodiester Bond

The phosphodiester bond is an esterification located between the phosphate group at position 5' of one nucleotide and the hydroxyl group on carbon 3' of another nucleotide. This forms the backbone...

Vineyard Soil

The soil supports the root structure of the vine and influences the drainage levels and amount of minerals and nutrients that the vine is exposed to. The ideal soil condition for a vine is a layer of thin topsoil and subsoil that sufficiently retains water but also has good drainage so that the roots do not become overly saturated. The ability of the soil to retain heat and/or reflect it back up to the vine is also an important consideration that affects the ripening of the grapes.

Annual Cycle of a Vineyard

The annual cycle of a vineyard includes pruning, cutting, trellising maintenance, anchoring, budburst, ploughing down, de-budding, suckering, flowering, first trimming, first leaf thinning, green harvesting, 2 leaf thinning,...

The Nervous System

Central Nervous System (CNS)

Brain

Located inside the head, the brain is divided into three regions:

• Cerebrum: Receives and interprets information from the sense organs. Language, memory, learning, and thinking are located here.
• Cerebellum: Plays an important role in motor control and motor learning. It acts in coordination and precision.
• Brain Stem: Joins the brain and spinal cord. It controls involuntary actions.

Spinal Cord

A long, thin tube running inside the backbone, the spinal cord transports information from the brain to the nerves and carries reflexes.

Protection of the CNS

• Hard: Bones protect the CNS. The brain is protected by the skull, and the spinal cord is protected by the backbone.
• Soft: Meninges, a system of membranes