The Nervous System: Parts and Functions

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Questions and Answers

Which of the following accurately describes the relationship between the central nervous system (CNS) and the peripheral nervous system (PNS)?

  • The PNS is responsible for complex cognitive functions, while the CNS handles simple reflexes.
  • The CNS controls involuntary actions, while the PNS governs voluntary movements.
  • The PNS processes information, while the CNS solely relays signals.
  • The CNS consists of the brain and spinal cord, acting as the control center, while the PNS transmits signals between the CNS and the rest of the body. (correct)

If a person sustains damage to their cerebellum, which of the following functions would be most directly affected?

  • Memory and emotional processing.
  • Coordination of balance and smooth movements. (correct)
  • Regulation of heartbeat and breathing.
  • Processing sensory information from the skin.

During a stressful situation, such as narrowly avoiding a car accident, which division of the autonomic nervous system is primarily activated, and what are the expected physiological responses?

  • Sensory; heightened awareness of auditory and visual stimuli.
  • Somatic; voluntary muscle contractions for immediate action.
  • Parasympathetic; decreased heart rate, constricted pupils, increased digestion.
  • Sympathetic; increased heart rate, dilated pupils, redistribution of blood to muscles. (correct)

What distinguishes sensory neurons from motor neurons in terms of function and direction of signal transmission?

<p>Sensory neurons transmit signals from sensory receptors to the CNS, while motor neurons carry signals from the CNS to muscles or glands. (A)</p> Signup and view all the answers

How do hormones released by the anterior pituitary gland influence the function of other endocrine glands in the body?

<p>They stimulate or inhibit hormone production in other endocrine glands. (A)</p> Signup and view all the answers

During which stage of protein synthesis is mRNA directly involved, and what is its specific role?

<p>Translation; serving as the template for tRNA to bring appropriate amino acids to the ribosome. (D)</p> Signup and view all the answers

What is the primary role of the hypothalamus in coordinating the nervous and endocrine systems, and how does it achieve this?

<p>It monitors internal conditions and signals the pituitary gland to release hormones. (A)</p> Signup and view all the answers

How does the interaction between FSH and LH differ in males and females regarding hormone production and reproductive function?

<p>In males, FSH stimulates sperm production, and LH stimulates testosterone production, while in females, FSH stimulates egg maturation, and LH triggers ovulation. (B)</p> Signup and view all the answers

Which of the following statements accurately describes the concept of negative feedback in hormonal regulation, and provides a relevant example?

<p>It counteracts changes to maintain homeostasis, such as high levels of estrogen and progesterone inhibiting FSH and LH secretion after ovulation. (B)</p> Signup and view all the answers

What distinguishes analogous structures from homologous structures in the context of evolutionary biology, and provides an example of each?

<p>Analogous structures have similar functions but different evolutionary origins (e.g., wings of insects and birds), while homologous structures have similar structure and common ancestry (e.g., limbs of humans and bats). (C)</p> Signup and view all the answers

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Flashcards

Nervous System

Coordinates body activities by transmitting electrical signals for immediate responses (reflexes) and long-term processing (thinking, decision-making).

Cerebrum

The largest part of the brain, controlling higher cognitive functions like thinking, reasoning, memory, emotion, and voluntary movement. Divided into left (logic) and right (creativity) hemispheres.

Cerebellum

Located under the cerebrum; coordinates voluntary movements like posture, balance, and coordination, ensuring smooth and accurate movements.

Brainstem

Includes the medulla oblongata (controls vital functions), pons (links cerebellum and cerebrum, controls sleep), and midbrain (visual/auditory reflexes).

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Somatic Nervous System (SNS)

Controls voluntary movements by sending signals from the CNS to skeletal muscles.

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Autonomic Nervous System (ANS)

Controls involuntary bodily functions (heart rate, digestion, respiration); includes sympathetic ('fight or flight') and parasympathetic ('rest and digest') systems.

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Dendrites

Branch-like structures on neurons that receive electrical impulses from other neurons.

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Axon

A slender projection of a neuron that transmits electrical impulses to other neurons or muscles.

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Testosterone

The primary male sex hormone that promotes the development of male secondary sexual characteristics and regulates sperm production.

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Positive Feedback

Amplifies a change, moving a system away from a set point (e.g., increased estrogen stimulates more LH release during ovulation).

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Study Notes

  • Nervous and endocrine systems crucial for coordinating body activities.

Parts and Functions of the Nervous System

  • Nervous system uses electrical signals for immediate (reflexes) and long-term responses (thinking).
  • Central Nervous System (CNS) consists of the brain and spinal cord.

Brain

  • Cerebrum: Largest part, controls cognitive functions, divided into left (logic/language) and right (creativity/spatial) hemispheres.
  • Cerebellum: Coordinates movement, posture, balance for smooth, accurate actions; located under cerebrum.
  • Brainstem: Vital functions, includes medulla oblongata (heartbeat, breathing), pons (links cerebellum/cerebrum, sleep), midbrain (reflexes).

Spinal Cord

  • Connects brain to body, pathway for nerve signals.
  • Processes reflexes independently for quick reactions.

Peripheral Nervous System (PNS)

  • Somatic Nervous System: Voluntary movement via CNS signals to skeletal muscles.
  • Autonomic Nervous System (ANS): Involuntary functions, divided into sympathetic and parasympathetic.
  • Sympathetic Nervous System: "Fight or flight," increases heart rate, redistributes blood.
  • Parasympathetic Nervous System: "Rest and digest," slows heart rate, promotes digestion.
  • Sensory Division: Sensory information to CNS.
  • Motor Division: Signals from CNS to muscles and glands.

Neurons

  • Structure of Neurons:
  • Dendrites receive impulses.
  • Axon transmits impulses.
  • Myelin Sheath speeds transmission.
  • Node of Ranvier regenerates action potentials.
  • Axon Terminals release neurotransmitters.
  • Types of Neurons:
  • Sensory Neurons: Sensory receptors to CNS.
  • Motor Neurons: CNS to muscles/glands.
  • Interneurons: CNS relay between sensory/motor.

Parts and Functions of the Endocrine System

  • Endocrine system regulates body processes via hormones through bloodstream to target organs.

Key Endocrine Glands

  • Hypothalamus: Nervous/endocrine link, monitors internal conditions and signals pituitary.
  • Pituitary Gland: "Master gland" produces many hormones.
  • Anterior Pituitary: GH, TSH, ACTH, FSH, LH regulate other endocrine glands.
  • Posterior Pituitary: Oxytocin (childbirth/lactation), ADH (water balance).
  • Thyroid Gland: Neck, produces T4 and T3 for metabolism, growth, temperature.
  • Parathyroid Glands: Behind thyroid, PTH regulates calcium.
  • Adrenal Glands:
  • Adrenal Medulla: Adrenaline and noradrenaline for stress; increase heart rate/blood pressure.
  • Adrenal Cortex: Cortisol for stress response, regulates metabolism/immune.
  • Pancreas:
  • Insulin: Lowers blood sugar by cells absorbing glucose.
  • Glucagon: Raises blood sugar by glucose released from liver.
  • Gonads:
  • Ovaries: Estrogen (female characteristics/menstrual cycle), progesterone (uterus preparation).
  • Testes: Testosterone (male characteristics/reproductive functions).

Parts and Functions of the Human Reproductive System

  • The reproductive system ensures continuation of species.

Male Reproductive System

  • Testes: Sperm/testosterone production in seminiferous tubules.
  • Epididymis: Sperm maturation/storage.
  • Vas deferens: Sperm transport tube.
  • Seminal Vesicles: Seminal fluid for sperm nourishment/protection.
  • Prostate Gland: Adds fluids to semen, propels sperm.
  • Penis: Sperm to female reproductive system.

Female Reproductive System

  • Ovaries: Eggs/hormones (estrogen, progesterone).
  • Fallopian Tubes: Transport eggs; fertilization occurs here.
  • Uterus: Fertilized egg implantation/development.
  • Cervix: Lower uterus, dilates for childbirth.
  • Vagina: Connects uterus to outside, birth canal, receives sperm.

Role of Hormones in the Male and Female Reproductive System

  • Hormones regulate reproductive organ function, menstrual cycle, pregnancy, sperm production.

Male Hormones

  • Testosterone: Male characteristics, sperm production.
  • FSH and LH: Stimulate sperm/testosterone production.

Female Hormones

  • Estrogen: Female characteristics, menstrual cycle.
  • Progesterone: Uterus preparation.
  • FSH and LH: Regulate menstrual cycle, egg maturation/release.

Coordinated Functions of the Endocrine and Nervous Systems in Maintaining Homeostasis

  • Homeostasis: Body's stable internal environment.
  • Nervous system: rapid responses; endocrine: slower, hormonal control. These systems work together to maintain balance in the body.
  • Body temperature regulation: Hypothalamus signals cooling and releases hormones to dilate vessels.
  • Stress response: Nervous system activates adrenaline release for "fight or flight."

Feedback Mechanisms Involved in the Female Reproductive System

  • Feedback mechanisms regulate hormonal levels to ensure proper functioning of the reproductive system.
  • Positive Feedback: amplifies change (e.g., Estrogen increasing LH during ovulation)
  • Negative Feedback: counteracts changes, restoring set point (e.g., Estrogen/progesterone inhibiting FSH/LH after ovulation)

Chemical Compositions of DNA and RNA

  • DNA (Deoxyribonucleic Acid): and RNA (Ribonucleic Acid) are nucleic acids that carry genetic information.
  • DNA: Double helix, deoxyribose sugar, bases A-T, C-G, stores genetic information. Found in eukaryotic cells.
  • RNA: Single-stranded, ribose sugar, uses uracil (U) instead of thymine, involved in translating information from DNA.
  • messenger RNA (mRNA): Carries genetic code from DNA to ribosome.
  • transfer RNA (tRNA): Brings amino acids to ribosome.
  • ribosomal RNA (rRNA): Makes up the structure of the ribosome.

Protein Synthesis

  • Protein synthesis: cells make proteins in Transcription and Translation.
  • DNA Replication: DNA duplicates for new cells.
  • Helicase unwinds DNA.
  • DNA polymerase adds nucleotides.
  • Transcription: mRNA from template.
  • RNA polymerase unwinds DNA.
  • RNA polymerase adds RNA nucleotides (A-U, T-A, C-G, G-C).
  • Translation: mRNA code makes proteins at ribosome.
  • Ribosome binds mRNA/reads codons.
  • tRNA brings amino acids.
  • Amino acids linked by peptide bonds.
  • Codon: mRNA nucleotide sequence coding for amino acid.
  • Anticodon: tRNA sequence pairing with mRNA codon.

Types of Mutation

  • Mutation: DNA sequence change, caused by errors or factors like radiation. Mutations can lead to genetic variation.
  • Point Mutation: Single nucleotide change.
  • Substitution: One base replaces another.
    • Silent: Substitution doesn't change protein.
    • Missense: Results in different amino acid.
    • Nonsense: Creates stop codon, leading to premature termination.
  • Insertion: Extra nucleotide added.
  • Deletion: Nucleotide removed.
  • Frameshift Mutation: Insertion/deletion changing mRNA reading frame.
  • Chromosomal Mutation: Large-scale changes.
    • Duplication: Section duplicated.
    • Inversion: Segment reversed.
    • Translocation: Segment transferred.
    • Deletion: Part lost.
  • Effects of Mutations:
    • Beneficial: Advantageous traits.
    • Harmful: Diseases/malfunctions.
    • Neutral: No effect.

Evidence that Supports the Concept of Evolution

  • Evolution: Supported by fossil, comparative anatomy, molecular biology, biogeography.
  • Fossil Evidence: History of life and species' change.
  • Transitional fossils: Intermediate forms.
  • Comparative Anatomy:
    • Similarities/differences suggest common ancestry.
    • Homologous structures: Similar due to common ancestry.
    • Analogous structures: Similar function, different origins.
  • Vestigial structures: Lost original function.
  • Molecular Biology:
    • DNA/RNA/protein comparisons suggest common ancestry.
    • Gene homology: Similar genes suggest common ancestor.
  • Biogeography:
    • Geographic distribution supports evolution.
    • Species close geographically are related.
    • Adaptive radiation: Ancestral species diversify into different forms.
  • Embryology:
    • Similar embryo development indicates similar history. -Vertebrate embryos show similarities in early stages, such as the presence of pharyngeal pouches (which may become gills or other structures in different species).

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