SciOly Prep

What is the primary function of the brain?

The brain is the control center for all bodily functions, including thinking, breathing, moving, and feeling.

How many neurons are approximately in the human brain?

Approximately 86 billion neurons.

What are the three main regions of the brain?

The Cerebrum, the Cerebellum, and the Brainstem.

What is the largest part of the brain and what are its main functions?

The Cerebrum is the largest part of the brain, responsible for thinking, memory, and voluntary movement.

What role does the Cerebellum play in the brain?

The Cerebellum is responsible for balance and coordination.

What does the Brainstem connect and what does it control?

The Brainstem connects the brain to the spinal cord and controls automatic body functions like breathing and heartbeat.

What is the Limbic System involved in?

The Limbic System is involved in emotions and memory.

What are gyri and sulci in relation to the brain's surface?

Gyri are the ridges or bumps on the brain's surface, while sulci are the shallow grooves between gyri.

What is the function of the fissures in the brain?

Fissures are deep grooves that divide major parts of the brain.

What are the major functions of the Frontal Lobe?

The Frontal Lobe controls thinking, emotions, personality, judgment, self-control, movement, and memory.

What sensory information does the Parietal Lobe process?

The Parietal Lobe processes touch and integrates sensory information.

What is the primary responsibility of the Occipital Lobe?

The Occipital Lobe is primarily responsible for processing vision.

What functions does the Insular Lobe serve?

The Insular Lobe plays a role in taste, sensory-motor processing, risk-reward behaviors, and auditory/vestibular functions.

What is the Cerebral Cortex and its functions?

The Cerebral Cortex is the outermost layer of the cerebrum, responsible for memory, thinking, learning, reasoning, problem-solving, emotions, consciousness, and sensory processing.

What is a neural impulse?

A neural impulse is a fast electrochemical signal that travels through a neuron, enabling communication between neurons and the body.

What are the main parts of a neuron?

Dendrites, Cell Body (Soma), Axon, and Axon Terminals.

What is the function of the Myelin Sheath?

The Myelin Sheath is a fatty coating that speeds up impulse transmission.

What are Nodes of Ranvier?

Nodes of Ranvier are gaps in the myelin sheath that help the signal jump, facilitating faster transmission.

What are the types of neurons?

Sensory Neurons (afferent), Motor Neurons (efferent), and Interneurons.

What role do Glial Cells play in the nervous system?

Glial Cells support neurons and include Astrocytes (support, nutrients), Oligodendrocytes/Schwann Cells (myelin), and Microglia (immune defense).

What is the resting membrane potential of a neuron?

At rest, neurons have a negative charge inside (around -70 mV) and a positive charge outside.

What occurs during an action potential?

When the threshold (around -55 mV) is reached, Na⁺ channels open, causing depolarization, followed by K⁺ channels opening for repolarization.

What is the difference between saltatory conduction and conduction in unmyelinated axons?

Saltatory conduction is faster as the action potential jumps between Nodes of Ranvier in myelinated neurons.

What is a synapse and how do neurotransmitters function within it?

A synapse is the small gap between neurons where signals are transmitted via neurotransmitters.

What are some examples of neurotransmitters and their roles?

Examples include Acetylcholine (ACh), Dopamine, Serotonin, GABA, and Glutamate, each playing various roles in neural communication.

What does the Central Nervous System (CNS) consist of?

The CNS includes the brain and spinal cord, acting as the body's command center.

What does the Central Nervous System (CNS) include?

The brain and spinal cord.

What protects the Central Nervous System?

The skull, vertebrae, meninges, and cerebrospinal fluid (CSF).

What is the organization of the spinal cord?

It consists of gray matter (inside) and white matter (outside).

What is the role of reflex arcs in the spinal cord?

They control reflexes independently of the brain, involving sensory receptors, sensory neurons, interneurons, motor neurons, and effectors.

What are the components of the brainstem?

The Midbrain (visual/auditory reflexes), Pons (connects cerebrum/cerebellum, regulates breathing), and Medulla Oblongata (controls heartbeat, breathing, digestion).

What is the significance of damage to the brainstem?

It is life-threatening.

How many pairs of cranial nerves are there, and what do they control?

There are 12 pairs of cranial nerves that control functions of the face, head, neck, and some internal organs.

What are the three protective layers of the meninges?

Dura Mater, Arachnoid Mater, and Pia Mater.

What is the function of cerebrospinal fluid (CSF)?

It cushions the brain and spinal cord, circulates nutrients, and removes waste.

What are the two types of sleep cycles?

NREM (body rests, brain waves slow) and REM (dreaming, active brain, still body).

What does the Peripheral Nervous System (PNS) include?

All nerves outside the CNS, including cranial nerves, spinal nerves, and ganglia.

What are neural ganglia?

Clusters of neuron cell bodies in the PNS that act as mini processing stations.

What is the role of sensory neurons in the PNS?

They bring signals into the CNS.

What is the function of motor neurons in the PNS?

They send signals out from the CNS.

What does the somatic nervous system control?

Voluntary movement.

What does the autonomic nervous system control?

Involuntary functions.

What is the sympathetic division of the autonomic nervous system responsible for?

It prepares the body for action, increasing alertness and heart rate, using norepinephrine.

What is the parasympathetic division of the autonomic nervous system responsible for?

It calms the body, slows heart rate, and conserves energy, using acetylcholine.

What is proprioception?

The body's sense of its position in space, using receptors in muscles, joints, and the inner ear.

What are the classes of hormones in the endocrine system?

Steroid hormones, amine hormones, and peptide hormones.

How do water-soluble hormones act?

They bind to cell membrane receptors, triggering intracellular signaling pathways.

What are the effects of hyposecretion and hypersecretion of hormones?

Hyposecretion leads to too little hormone, while hypersecretion leads to too much hormone, causing dysfunction.

What is the role of the hypothalamus in the endocrine system?

It controls the pituitary gland and regulates basic drives.

What does the pituitary gland do?

It produces hormones that regulate other endocrine glands.

What hormones does the thyroid gland produce?

T3, T4 (regulating metabolism), and calcitonin (lowering blood calcium).

What hormones do the adrenal glands produce?

Cortisol and aldosterone (cortex) and epinephrine/norepinephrine (medulla) in response to stress.

What hormones does the pancreas produce?

Insulin and glucagon to regulate blood sugar.

What is the function of sex hormones produced by the gonads?

They are involved in reproduction and sexual maturity.

What are the primary functions of the gonads?

The gonads (ovaries and testes) produce sex hormones for reproduction and sexual maturity.

What hormone does the pineal gland produce and what is its function?

The pineal gland produces melatonin to regulate sleep-wake cycles.

What is the role of the thymus in the immune system?

The thymus produces thymosin, which is essential for T-cell development.

What are the three classifications of sense receptors?

Sense receptors can be classified structurally (Encapsulated Endings, Free Nerve Endings, Specialized Receptors), locationally (Interoceptors, Proprioceptors, Exteroceptors), and functionally (Thermoreceptors, Photoreceptors, Mechanoreceptors, Chemoreceptors, Nociceptors).

What do mechanoreceptors respond to and where are they found?

Mechanoreceptors respond to mechanical forces like pressure and vibration and are found in the skin, inner ear, muscles, tendons, and joints.

How do thermoreceptors function in the body?

Thermoreceptors detect temperature changes; peripheral thermoreceptors are near the skin surface, while central thermoreceptors monitor core body temperature.

What stimuli do nociceptors detect?

Nociceptors detect pain from mechanical, thermal, or chemical stimuli and are usually free nerve endings.

What are the functions of photoreceptors in the eye?

Photoreceptors in the retina include rods, which detect dim light and motion, and cones, which detect color and detail in bright light.

What is the role of chemoreceptors in the sensory system?

Chemoreceptors detect chemical stimuli and are crucial for taste and smell, with olfactory chemoreceptors in the nose and gustatory chemoreceptors on the tongue.

What do proprioceptors sense?

Proprioceptors sense body position, movement, and balance, and are located in muscles, tendons, and joints.

What distinguishes general senses from special senses?

General senses are scattered throughout the body and provide information about touch, pressure, pain, temperature, itch, and proprioception, while special senses are clustered in specialized organs and provide detailed information about vision, hearing, balance, smell, and taste.

What are the main structures of the eye and their functions?

The eye has three main layers: Fibrous (sclera, cornea), Vascular (choroid, ciliary body, iris), and Inner (retina with rods and cones). Light travels through these layers to reach the retina, where photoreceptors convert light into nerve impulses.

How does the ear contribute to hearing and balance?

The ear is divided into Outer, Middle, and Inner sections; sound waves travel through the auditory canal, vibrate the eardrum, are amplified by ossicles, and stimulate hair cells in the cochlea. Balance is managed by the vestibule and semicircular canals.

What is the function of olfactory receptors?

Olfactory receptors in the nasal cavity detect airborne molecules and send signals to the brain, playing a role in detecting hazards and enhancing taste.

How do taste buds function in the sensory system?

Taste buds on the tongue detect dissolved food chemicals and send signals to the gustatory cortex, identifying five basic tastes: sweet, salty, sour, bitter, and umami.

What are some common vision disorders?

Common vision disorders include Myopia (nearsightedness), Hyperopia (farsightedness), Presbyopia (age-related), Nyctalopia (night blindness), Astigmatism (blurry vision), Conjunctivitis (pink eye), and Color Blindness.

What are some common ear disorders?

Common ear disorders include Otitis Media (middle ear infection) and types of hearing loss such as Conductive and Sensorineural Deafness.

What are some disorders related to smell and taste?

Disorders include Anosmia/Dysosmia (loss/distortion of smell) and Dysgeusia (altered taste).

What is the focus of classical genetics?

Classical genetics studies genes, their inheritance, and variation, based on Mendelian principles.

Who is considered the pioneer of genetics and what did he discover?

Gregor Mendel is considered the pioneer of genetics; he discovered fundamental laws of inheritance through his experiments with pea plants.

What is a chromosome?

A chromosome is the largest unit of genetic material.

What is the difference between diploid and haploid?

Diploid refers to two sets of chromosomes, while haploid refers to one set of chromosomes found in gametes.

What is a gene?

A gene is a heritable trait.

What is an allele?

An allele is a different form of the same gene.

What does genotype refer to?

Genotype refers to the full hereditary information, such as AA, Aa, or aa.

What is a genotype?

The full hereditary information of an organism (e.g., AA, Aa, aa).

What is a phenotype?

The observable physical traits of an organism (e.g., black fur, green fur).

What distinguishes dominant alleles from recessive alleles?

A dominant allele produces a visible phenotype with one copy, while a recessive allele requires two copies to display its phenotype.

What are homozygous and heterozygous individuals?

Homozygous individuals have two identical alleles (AA or aa), while heterozygous individuals have two different alleles (Aa) and display the dominant phenotype.

What is a wild-type allele?

The most common allele in a population.

What is a pedigree?

A family tree used to track phenotypes across generations, with males represented by squares and females by circles.

What is the purpose of a Punnett square?

To predict the possible genotypes of offspring based on parental allele contributions.

What is a monohybrid cross?

A genetic cross examining one gene.

What is a dihybrid cross?

A genetic cross examining two genes, assuming Mendel's Law of Independent Assortment.

What are linked genes?

Genes located on the same chromosome that tend to be inherited together.

What is recombination frequency (Rf)?

The percentage of recombinant offspring, with 1% Rf equaling 1 centimorgan (map unit).

What is sex linkage?

The inheritance pattern of genes located on the X chromosome, where males are hemizygous for X-linked genes.

Why are X-linked recessive traits more common in males?

Because males have only one X chromosome, a single recessive allele will express the recessive phenotype.

What is a phenotypic ratio?

A ratio that provides shortcuts for predicting inheritance patterns (e.g., 3:1 for monohybrid crosses).

What is the product rule in genetics?

A probability rule used to calculate the likelihood of multiple independent outcomes.

What is sickle cell disease?

An example of an autosomal recessive disorder.

What are genes?

Specific DNA sequences that code for functional RNA molecules.

What is the structure of DNA?

A double-stranded, antiparallel molecule forming a double helix, with a sugar-phosphate backbone and nitrogenous bases (A, T, C, G).

What does Chargaff's Rule state?

A always pairs with T, and G always pairs with C.

What is the Central Dogma of Biology?

The process of gene expression where DNA is transcribed to RNA, which is then translated to protein.

What is a point mutation?

A change in DNA sequence at a single nucleotide, which can be silent, missense, or nonsense.