3.3 The Nervous System

Receives information from the receptors, processes and coordinates it, and generates orders for the effectors. It is made up of the central nervous system or CNS, and the peripheral nervous system or PNS.

3.4 The Central Nervous System or CNS

Coordinates all the body's functions. It is formed by the encephalon and the spinal cord.

The Encephalon

Protected by the skull or cranium and by three membranes, the meninges, between which a liquid called the cerebrospinal fluid circulates. This liquid protects the encephalon from knocks and blows. Divided into three parts:

• The brain is divided into two hemispheres, which are separated by a fissure. Its surface, the cerebral cortex, is full of folds and furrows, known as circumvolutions.

Regulation of Enzyme Activity

Enzymes are the workhorses of cells, catalyzing the thousands of biochemical reactions that keep cells alive and functioning. The activity of enzymes is carefully controlled to ensure that the proper amount of product is produced at the right time.

Why Regulate Enzyme Activity?

There are several reasons why cells need to regulate enzyme activity. First, the concentration of substrates and products can vary widely within the cell. If enzyme activity were constant, the rate of the reaction would also vary wildly, depending on the availability of substrates. Regulation allows the cell to adjust the rate of the reaction to match the needs of the cell.

Second, the cell needs to coordinate the activities of different enzymes... Continue reading "Enzyme Regulation: Mechanisms and Examples" »

Chapter 5: Life Processes

Introduction

Life processes are the basic functions performed by living organisms for survival and body maintenance. These include nutrition, respiration, transportation, and excretion.

Nutrition

There are two modes of nutrition: autotrophic and heterotrophic.

Autotrophic Nutrition (Photosynthesis)

Photosynthesis is the process by which green plants synthesize their own food using carbon dioxide (CO₂) and water (H₂O) in the presence of chlorophyll and sunlight.

Raw Materials for Photosynthesis: Carbon dioxide and water.

Site of Photosynthesis: Chloroplasts in the leaves. Chloroplasts contain a green pigment called chlorophyll.

Main Events of Photosynthesis:

• Absorption of light energy by chlorophyll.
• Conversion of light energy

Valve Disorders

Valve disorders can be caused by congenital deformities or acquired diseases. Stenosis (narrowing) restricts blood flow. Structural malformations prevent the valve from closing properly, causing murmurs. These often present with other cardiac conditions/disorders. Athletes with electrical (arrhythmia) or structural changes (hypertrophy) may have limitations on their ability to play.

Mitral Valve Prolapse

Mitral valve prolapse prevents the valve from closing properly and is the most common valve disorder. Return to play (RTP) is often possible if there is no significant family history.

Systemic Hypertension

Systemic hypertension is common in athletes but is not the etiology of sudden cardiac death (SCD). The pathogenesis involves... Continue reading "Understanding Cardiovascular Conditions in Athletes" »

Human reproduction is sexual. Two individuals from different sexes are needed. Each produces a type of gamete (reproductive cell).

Embryo development: Zygote undergoes cell division until it becomes an embryo that continues development up to being a fetus.

Childbirth: Baby is born, alive and fully formed

Development: The baby grows until maturity is reached (adulthood)

Changes leading to sexual maturity

• Primary sex characteristics: The reproductive organs
• Puberty: Stage from the ages 10-16, when majority occurs
• Adolescence: From puberty to adulthood, physical maturity and physiological and social changes, sexual desire appears
• Sex

Female Reproductive System

Key Components and Functions

Uterus

The myometrium, the middle layer of the uterine wall, is responsible for the contractions during childbirth.

Vagina

The vagina is an elastic tube that facilitates penetration during sexual intercourse.

Vulva

The vulva, the external female genitalia, consists of the labia majora, labia minora, and the clitoris, which is responsible for sexual pleasure.

Bartholin's Glands

These glands produce lubricant to facilitate sexual intercourse.

The Ovarian Cycle

Each ovarian cycle lasts approximately 28 days and consists of three phases:

1. Follicular Phase (14 days): An egg cell matures.
2. Ovulation: The mature egg is released from the ovary into the fallopian tube.
3. Luteal Phase (14 days): The corpus luteum,

Identical twins: once fertilization happens zygot break in two Different cells and each one give a different person but as they have the same Genes they are identical.

Contraceptivemethods (is not going to be asked at exam)

Assisted reproduction

Artificial insemination: sperm is placed inside the uterus During ovulation period using a syringe

IVF In vitro fertilization they get egg cell and join them With sperm using a microscope, once fertilization and the zygote develop to Blastocyst it is implanted in the uterus.

Ecosystem

Abiotic (physical, chemical), Biotic (population mateixa, community totes)

get food by: feeding, trophic relation shipsTrophic levels: 1) Producers 2)Consumers 3)Decomposers (bacteria, fungi)Organic materials: from living beings.
Photosynthesis: plants absorve inorganic matter(CO2, H2O, Sunlight) and produce organic matter (glucose, oxygen). Is produced in the clorophila (on cloroplasts). Nutritions: (1) autotrophs (photo and chemo), (2,3) heterotrophs (no photo)In a population relation of feeding: Cannibalism *mothers eat offspringChemoautotrophs: on acuatic volcanos 5km under sea,there were bacteria that do the chemosynthesi (because sunlight doesn't arrive): convert inorganic matter into organic through chemical substances (methane,

Invertebrate Reproduction

Porifera (Sponges)

They perform both types of reproduction:

• Asexual Reproduction: A small piece of sponge breaks off, anchors to a surface, and regenerates into a complete organism.
• Sexual Reproduction: This requires two individuals of opposite sex. They form sexual cells (sperm and ovum) that join together and produce a larva. The larva then anchors to a surface and grows, forming a new individual.

Polyps

They reproduce both asexually and sexually:

• Asexual Reproduction: A small bud forms and remains attached as it grows. It separates from the parent organism only when mature and then anchors to a surface.
• Sexual Reproduction: This requires two individuals of opposite sex. They form sexual cells (sperm and ovum) that join

Head and Neck Anatomy

Meninges and Sinuses

Falx Cerebri

Located between the two cerebral hemispheres.

Falx Cerebelli

Located between the two cerebellar hemispheres.

Tentorium Cerebelli

Located between the cerebrum and cerebellum.

Single Sinuses

• Superior sagittal sinus
• Inferior sagittal sinus
• Straight sinus
• Occipital sinus
• Basilar sinus

Paired Sinuses

• Sphenoparietal sinus
• Cavernous sinus
• Superior petrosal sinus
• Inferior petrosal sinus
• Transverse sinus
• Sigmoid sinus

Cavernous Sinus

Site: Sphenoid bone, extending to the superior orbital fissure.

Size: 2cm long, 1cm wide.

Structures within the Lumen:

• Internal carotid artery
• Abducent nerve

Structures in the Lateral Wall:

• Oculomotor nerve
• Trochlear nerve
• Ophthalmic nerve
• Maxillary nerve

Tributaries:

• Ophthalmic vein
• Superficial middle