Notes, summaries, assignments, exams, and problems for Biology

Chemical Evolution

Chemical evolution refers to the processes that created the biomolecules, and then formed structures called protocells. According to Oparin, the first biomolecules were synthesized when the components of Earth’s primitive atmosphere reacted on contact with each other.

Biological Evolution

Biological evolution refers to the processes that led protocells to become different types of cells, and resulted in all the different organisms ever to have inhabited the Earth. Different types of prokaryotic cells were created from primitive cells: heterotrophic cells, photosynthetic cells, aerobic cells, long and very mobile cells.

Fixist Theories

Fixist theories uphold the idea that the species that currently exist on Earth were created... Continue reading "Chemical and Biological Evolution Theories and Characteristics of Hominids" »

Lower Canine

Root may bifurcate into 2 divisions

Chron:

• Enamel: 6-7 y.o
• Eruption: 9-10 y.o
• Root: 12-13 y.o

Geo:

• Lng/lab: pentagon/trapezoid, short side cervical

Mes-Dis:

• Triangular base cervical

Incis:

• Diamond

Labially:

• Cervical ridge/labial ridge/mes-dis development grooves

Lingually:

• Cingulum/lingual ridge/mes-des marginal ridge/1 lingual fossa

Mesial Contact:

• Incisal third

Distal Contact:

• Middle third

Pulp Cavity:

• 1 pulp horn/oval shaped transversally

Cusp Length:

• Distal side is longer

Upper First Premolar

Mesial Marginal Developmental Groove/Canine Fossa

Chro:

• Enamel: 5-6 y.o
• Eruption: 10-11 y.o
• Root: 12-13 y.o

Geo:

• Lng/Bucc: Trapezoid; short side cervical

Mes-Dis:

• Trapezoid; long side cervical

Occlu:

• Hexagonal

Buccally:

• Cervical/Buccal Ridge/Mes-Dis Buccal Developmental Groove

Mesially:

Digestive Process

Key Components of the Digestive System

• Epiglottis: A flap of cartilage at the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe.
• Esophagus: The tube that extends from the throat to the stomach.
• Lower Esophageal Sphincter: A bundle of muscles at the low

What Makes a Living Thing ‘Living’?

Non-Living Things

Non-living things are made up of inorganic matter. The most abundant chemical elements that make up inorganic matter are: oxygen (O), silicon (Si), aluminum (Al), and iron (Fe).

Living Things

All living things, also called organisms, are made up of the same chemical elements.

The elements that form part of living matter are known as bioelements.

The six most abundant bioelements are: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S). They make up more than 90% of living matter. The atoms and molecules of bioelements combine with each other through chemical reactions, producing biomolecules. Biomolecules may be:

• Inorganic, such as water and mineral salts.
• Organic

es 3:       x        Cornea                         1   1    2      Dendrites: receive the 

All

Long

I-Parkinson Sx(Amimia/Micrgraphia)(dementia/hyperkinesia)II-2nd Park(Neuroleptic)(CO/Arteriscleoris/encephlaiits)III-Syringomyelia(Sensory loss/Wasting/Long tract/Autonomiv)IV-Tx of M Gravis(Ach(-)(CSD)(Plasmophoresis)(thymectomy)V-Foot Drop(L5...)VI-Open Depressed ScullVII-Cerebral artery aneurysm!(gigantic,sacular)VIII-Sterotactic Techniques used for:^^glioblastoma Histology-Lumbar vertebral Fractures:-Sx provoked by brain tumour!-Multifocal Tumours:-Dx for Cerebral artery aneurysm-Cerebral artery naeurysm Clipped by:

-CN 9+10 Dx:-Lesion CN 5(sensory nuclei)-CN 9 lesion!-Malingnant brain glioma

***T/F:

-CS tract(NOT ) onl from Frontal-BS lesion--->controlateral hemiparesis(T)-Bilateral amr paralysis, Central cord(T)-controlateral Focal

Key Concepts in Evolution

Species: A set of individuals that can reproduce with each other and create fertile offspring.

Speciation: A process driven by several factors:

• Natural selection: Natural selection favors some individuals over others.
• Genetic isolation: Members of two different populations within the same species can no longer reproduce with the other population.
• Gradual differentiation: After isolation, populations become increasingly different.
• Speciation: Over time, genetic changes produce such significant differences that it's no longer possible for two populations to produce fertile offspring.

Human Ancestors

• Australopithecus (6 million years ago): The first hominid, walked upright.
• Homo habilis (2.5 million years ago): Used rudimentary

Interaction and Homeostasis

Interaction includes a series of processes whose object is to adapt the body to changing conditions in the internal and external environment. It connects and coordinates the different parts of our body so that they work together.

Homeostasis is the process that maintains the body's stability when there are changes in the internal environment. This process works as a feedback device, meaning that when a variation is detected in a particular element, a series of mechanisms in the body start up to make the variation return to its normal state.

Systems Participating in the Interaction Process

• Sensory Organs: Capture the stimulus, which is transformed into a nerve impulse and transmitted to the nervous system.
• Nervous System:

Steroid Hormones

Steroid hormones are a type of hormone consisting of four rings made of carbon atoms. They are derived from cholesterol and have three primary modes of action:

• Binding to membrane receptors
• Binding to and activating proteins in the cytoplasm
• Acting on receptors linked to chromosomes

Sex Hormones

Gonadal steroid hormones are produced by the gonads, which include the ovaries and testes. These hormones include:

• Androgens (e.g., testosterone, dihydrotestosterone)
• Estrogens
• Progesterone

It is important to note that gonads can produce both types of hormones, with the aromatase enzyme mediating conversions between them.

Organizing Effects of Sex Hormones

Organizing effects refer to the hormonal effects on the brain and genitals that occur during... Continue reading "Steroid and Sex Hormones: Organizing and Activating Effects" »