Endocrine System Overview
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Questions and Answers

What role does aldosterone play in the body's fluid balance?

Aldosterone is a mineralocorticoid that promotes water retention, decreases potassium levels, and raises blood pressure.

How do insulin and glucagon work together to regulate blood glucose levels?

Insulin lowers blood glucose levels by facilitating cellular absorption, while glucagon raises blood glucose levels by stimulating glucose release from the liver.

What is the function of the thymus gland in the immune system?

The thymus gland produces T-cells and thymosin, which are essential for the immune response.

What hormones are produced by the pineal gland, and what is their function?

<p>The pineal gland secretes melatonin, which regulates sleep cycles and circadian rhythms.</p> Signup and view all the answers

Describe the difference between the sympathetic and parasympathetic divisions of the autonomic nervous system.

<p>The sympathetic division prepares the body for 'fight or flight' responses, increasing heart rate, while the parasympathetic division promotes 'rest and digest' activities, slowing the heart rate.</p> Signup and view all the answers

What is the role of the myelin sheath in a neuron?

<p>The myelin sheath insulates the axon and speeds up the transmission of nerve impulses.</p> Signup and view all the answers

Explain how the sodium/potassium pump contributes to a neuron's resting potential.

<p>The sodium/potassium pump actively transports 3 sodium ions out and 2 potassium ions into the cell, creating a concentration gradient essential for the neuron's resting potential.</p> Signup and view all the answers

What happens to the thymus gland as a person ages, and what is the consequence of this change?

<p>The thymus gland atrophies and produces fewer T-cells as a person ages, leading to a weakened immune system.</p> Signup and view all the answers

Identify the main components of the Central Nervous System (CNS).

<p>The Central Nervous System is primarily composed of the brain and the spinal cord.</p> Signup and view all the answers

What is the significance of the Nodes of Ranvier in neuron function?

<p>Nodes of Ranvier facilitate the rapid transmission of nerve impulses by allowing ions to flow in and out of the neuron at specific points.</p> Signup and view all the answers

What is the resting membrane potential of a neuron, and what generates the nerve impulse?

<p>-70mv; the charge difference between sodium and potassium creates potential energy.</p> Signup and view all the answers

What happens during depolarization in a neuron?

<p>A neurotransmitter attaches to the receptor, causing ion channels to open and sodium to flow in.</p> Signup and view all the answers

What is the role of dopamine in the nervous system?

<p>Dopamine is involved in reward, motivation, pleasure, and motor function.</p> Signup and view all the answers

Describe the purpose of the reflex arc.

<p>To respond quickly to stimuli without involving the brain, enabling immediate reactions.</p> Signup and view all the answers

What structure connects the left and right hemispheres of the brain?

<p>Corpus callosum.</p> Signup and view all the answers

What are the main functions of the hypothalamus?

<p>Regulates homeostasis, hunger, thirst, and is connected to the pituitary gland.</p> Signup and view all the answers

How does the parasympathetic nervous system affect the body?

<p>It promotes rest and repose functions, such as slowing the heartbeat and stimulating digestion.</p> Signup and view all the answers

What are rods and cones, and what roles do they play in vision?

<p>Rods are responsible for night vision; cones are for color vision.</p> Signup and view all the answers

Explain the process of internal fertilization.

<p>Sperm and egg unite within the reproductive tract, typical in mammals and reptiles.</p> Signup and view all the answers

What is the function of the amniotic egg?

<p>It provides a self-contained environment for the developing embryo.</p> Signup and view all the answers

What changes occur in the corpus luteum if fertilization does not happen?

<p>It degenerates after about two weeks, leading to the shedding of the uterine lining.</p> Signup and view all the answers

What are the three germ layers formed during gastrulation?

<p>Endoderm, mesoderm, and ectoderm.</p> Signup and view all the answers

Describe the function of the cochlea in hearing.

<p>The cochlea converts sound waves into nerve impulses.</p> Signup and view all the answers

What is the primary cause of color blindness?

<p>It is a sex-linked trait more common in males due to the X chromosome.</p> Signup and view all the answers

What is the primary function of the endocrine system?

<p>To secrete hormones that regulate various metabolic processes.</p> Signup and view all the answers

How do peptide hormones differ from steroid hormones?

<p>Peptide hormones require a 'second messenger' to activate enzyme systems, while steroid hormones can enter cells and directly influence DNA.</p> Signup and view all the answers

What hormone stimulates the thyroid to release its hormones?

<p>Thyroid Stimulating Hormone (TSH).</p> Signup and view all the answers

What are the functions of the parathyroid hormone?

<p>It increases blood calcium levels by breaking down bone matrix.</p> Signup and view all the answers

What is the effect of growth hormone on the body?

<p>It controls overall growth and development, enhancing bone density and increasing muscle mass.</p> Signup and view all the answers

What is the role of calcitonin in calcium metabolism?

<p>Calcitonin lowers blood calcium levels by promoting calcium storage in bone.</p> Signup and view all the answers

What triggers the secretion of adrenal hormones during stress?

<p>Stressful situations stimulate the adrenal gland to release glucocorticoids and catecholamines.</p> Signup and view all the answers

What are gonads, and what hormones do they produce?

<p>Gonads are reproductive glands that produce estrogen and progesterone in ovaries and testosterone in testicles.</p> Signup and view all the answers

What is the function of antidiuretic hormone (ADH)?

<p>ADH conserves water and controls urine output.</p> Signup and view all the answers

How does iodine deficiency affect the thyroid gland?

<p>Iodine deficiency can prevent the production of thyroid hormones, leading to goiter.</p> Signup and view all the answers

Describe the feedback mechanism for calcium balance in the body.

<p>A negative feedback loop regulates calcium levels, with calcitonin lowering them and parathyroid hormone raising them as needed.</p> Signup and view all the answers

What hormone is responsible for stimulating milk production?

<p>Prolactin stimulates milk production in mammary glands.</p> Signup and view all the answers

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

<p>The hypothalamus regulates the release of hormones from the pituitary gland.</p> Signup and view all the answers

What are the two distinct parts of the adrenal gland?

<p>The outer part is called the cortex and the inner part is called the medulla.</p> Signup and view all the answers

Study Notes

Endocrine System

  • Secretes hormones to regulate metabolic processes
  • Ductless glands; hormones secreted directly into lymphatic and circulatory systems; no vessels
  • Hormones are chemical messengers affecting recipient cells' metabolism
  • Target specific organs due to distinct hormone receptors

Endocrine Glands

  • Head: Hypothalamus, pituitary, pineal gland
    • Hypothalamus: Affects aspects of biology; "master gland"
    • Pituitary gland: Secretes hormones, affecting various aspects of biology
    • Pineal gland: Produces melatonin
  • Neck: Thyroid, parathyroid glands (4)
  • Thoracic: Thymus
  • Abdominal: Pancreas (endocrine and exocrine); adrenal glands
  • Gonads: Ovaries, testes, placenta (only during pregnancy)

Hormones

  • Peptide hormones: Activate enzyme systems via "second messengers" (e.g., oxytocin, epinephrine); protein-based
  • Steroid hormones: Lipid-based; pass through cell membranes; activate certain DNA sections, leading to protein production

Hypothalamus and Pituitary

  • Located underneath the brain
  • Pituitary gland is the "master gland," directing hormonal activity

Thyroid Gland

  • Located in the throat region
  • Produces hormones like thyroxine (T4) and triiodothyronine (T3) requiring iodine
  • Regulates metabolism
  • Calcitonin: Lowers blood calcium levels by increasing calcium uptake from blood and storage in bones.
  • Parathyroid hormone: Increases blood calcium level by releasing calcium from bones

Adrenal Gland

  • Located atop each kidney
  • Adrenal cortex produces corticosteroids (e.g., cortisol); affect immune response and stress response
  • Adrenal medulla: Produces epinephrine and norepinephrine, responsible for short-term stress responses.

Pancreas

  • Endocrine and exocrine functions; secretes insulin and glucagon
  • Insulin decreases blood glucose levels, while glucagon increases them

Testes (Males)

  • Produces testosterone; responsible for secondary sexual characteristics

Ovaries (Females)

  • Produce estrogen and progesterone; responsible for secondary sexual characteristics
  • Progesterone levels influence pregnancy

Thymus Gland

  • Located in the chest
  • Produces T-cells (involved in immunity)

Pineal Gland

  • Located in the brain
  • Produces melatonin; regulates sleep cycles

Digestive Hormones

  • Gastrin stimulates gastric juice production
  • Secretin and Cholecystokinin stimulate pancreatic juice and bile release

Vertebrate Nervous System

  • Central Nervous System (CNS): Brain and Spinal Cord
  • Peripheral Nervous System (PNS): 12 cranial nerves and 31 spinal nerves, responsible for sensory and motor function (somatic and autonomic)
    • Somatic NS: Voluntary movements, connecting to skeletal muscle
    • Autonomic NS: Involuntary movements, connecting to cardiac, smooth muscles, and glands
  • Neuron (Nerve Cell): Basic functional unit
    • Cell body, axon, dendrites, myelin sheath, nodes of Ranvier, synaptic terminals
  • Nerve Impulse: Electrical signal traveling along neurons

Nerve Impulse

  • Sodium-Potassium Pump: Active transport of sodium and potassium ions across cell membrane to maintain resting potential
  • Resting Potential: Difference in electrical charge across the neuron membrane (-70mv)
  • Action Potential: Rapid change in membrane potential triggering nerve signal (-70 to +35mV)
  • Depolarization: Na⁺ ions move into the neuron, reducing the membrane potential
  • Repolarization: K⁺ ions move out of the neuron, restoring the membrane potential to resting
  • Synaptic Transmission: Chemical messengers (neurotransmitters) transmit signals across synapses between neurons
  • Neurotransmitters: Chemical messengers influencing postsynaptic cell
    • Cholinergic (Acetylcholine)
    • Biogenic amines (Dopamine, Norepinephrine, Serotonin)
    • Amino Acids (GABA, Glycine)
    • Nitric Oxide (NO)

Eye Anatomy

  • Outer (Sclera): Protective outer layer
  • Choroid: Contains blood vessels; supplies nutrients
  • Retina: Contains photoreceptors (rods and cones)
  • Cornea: Transparent front of the eye for light transmission
  • Lens: Focuses light onto the retina
  • Aqueous humor: Fluid found in the anterior chamber
  • Vitreous humor: Fluid in the posterior chamber
  • Fovea: The point on the retina where cone density is greatest for high detail vision

Ear Anatomy

  • Outer ear: Pinna and auditory canal (funnel sound)
  • Middle ear: Tympanic membrane (eardrum); ossicles (malleus, incus, stapes)
  • Inner ear: Cochlea (fluid-filled); auditory nerve

Reproductive Systems and Human Development

  • External fertilization: Fertilization outside the body (aquatic animals)
  • Internal fertilization: Fertilization inside the body (reptiles, birds, mammals)
  • External Embryo Protection: Jelly coats, amniotic eggs (reptiles, birds)
  • Mammals: Internal development; diverse reproductive strategies
  • Male reproductive system: Testes (produce sperm); testosterone (secondary sexual characteristics)
  • Female reproductive system: Ovaries (produce eggs); hormones
  • Fertilization: Sperm unites with egg; zygote formation
  • Embryonic development: Stages from zygote to mature organism
    • Cleavage: Cell division;
    • Morula: Solid ball of cells
    • Blastula: Hollow ball of cells
    • Gastrulation: Formation of three germ layers

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Bio Unit 5 Endocrine and Nervous System PDF

Description

This quiz explores the components and functions of the endocrine system, including various glands and hormones. It covers the roles of major glands such as the hypothalamus, pituitary, and thyroid, as well as the types of hormones they secrete. Test your knowledge of how these hormones regulate metabolic processes.

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