Autonomic Nervous System Overview
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Questions and Answers

What is the primary function of glucagon in the body?

  • To increase blood glucose levels (correct)
  • To decrease blood glucose levels
  • To promote fat storage
  • To stimulate cell division

Which condition results from the hypersecretion of growth hormone after the epiphyseal plates have closed?

  • Acromegaly (correct)
  • Insulin resistance
  • Dwarfism
  • Gigantism

What characterizes Type 1 Diabetes?

  • Hyperactivity of glucagon
  • Overproduction of insulin
  • Autoimmune destruction of beta cells (correct)
  • Insulin receptor desensitization

Which gland is NOT regulated by the pituitary gland?

<p>Parathyroid glands (A)</p> Signup and view all the answers

Which of the following hormones is primarily responsible for decreasing blood glucose levels?

<p>Insulin (C)</p> Signup and view all the answers

What is the primary function of the autonomic nervous system?

<p>Adjust the activity of glands and involuntary muscles (D)</p> Signup and view all the answers

Which division of the autonomic nervous system is primarily responsible for 'fight or flight' responses?

<p>Sympathetic nervous system (D)</p> Signup and view all the answers

Which neurotransmitter is primarily associated with the parasympathetic nervous system?

<p>Acetylcholine (B)</p> Signup and view all the answers

What is the role of visceral reflexes in the autonomic nervous system?

<p>Maintain homeostasis without conscious involvement (D)</p> Signup and view all the answers

Which of the following best describes the sympathetic nervous system's effect on blood flow during a stress response?

<p>Redirected blood flow to skeletal muscles (B)</p> Signup and view all the answers

In which anatomical area do sympathetic nerves predominantly originate?

<p>Thoracolumbar region (D)</p> Signup and view all the answers

What characteristic distinguishes the parasympathetic nervous system from the sympathetic nervous system?

<p>More selective actions (A)</p> Signup and view all the answers

Which nerve is responsible for carrying a significant portion of parasympathetic fibers?

<p>Vagus nerve (A)</p> Signup and view all the answers

Which part of the brain is primarily involved in the perception of pain modulation?

<p>Hypothalamus (B)</p> Signup and view all the answers

What type of cells in the taste buds are responsible for releasing neurotransmitters?

<p>Taste receptor cells (B)</p> Signup and view all the answers

Which of the following statements about olfactory cells is correct?

<p>They are replaced every 60 days. (C)</p> Signup and view all the answers

What is the primary function of the ossicles in the middle ear?

<p>Sound amplification (C)</p> Signup and view all the answers

Which structure in the nose detects odors?

<p>Olfactory mucosa (B)</p> Signup and view all the answers

What primarily determines the pitch of a sound?

<p>The frequency of the wave (B)</p> Signup and view all the answers

How does the auditory tube in children differ from that in adults?

<p>It is more horizontal and shorter. (C)</p> Signup and view all the answers

Which structure is responsible for the perception of static equilibrium?

<p>Utricle and saccule (C)</p> Signup and view all the answers

Which taste is specifically associated with alkaloids?

<p>Bitter (A)</p> Signup and view all the answers

How does loudness get determined in the auditory system?

<p>By the number of hair cells that bend (B)</p> Signup and view all the answers

What is the primary role of the basilar membrane in the cochlea?

<p>To convert vibrations into nerve impulses (C)</p> Signup and view all the answers

Which part of the ear does the tympanic membrane transmit vibrations to?

<p>Middle ear (C)</p> Signup and view all the answers

What role do otoliths play in the vestibular system?

<p>They provide weight to the membrane for head position changes (A)</p> Signup and view all the answers

Which type of equilibrium is associated with angular changes in rate of rotation?

<p>Dynamic equilibrium (D)</p> Signup and view all the answers

Which feature of the auditory system detects frequency ranges of high pitches?

<p>Basilarmembrane vibrating in the higher frequencies (D)</p> Signup and view all the answers

What is the function of the oculomotor nerve in relation to eye movement?

<p>Innervates the majority of extraocular muscles (B)</p> Signup and view all the answers

What structure in the eye is responsible for controlling the diameter of the pupil?

<p>Iris (D)</p> Signup and view all the answers

Which layer of the eye is highly vascular and contains pigment?

<p>Choroid (C)</p> Signup and view all the answers

What is the primary function of the vitreous body in the eye?

<p>Maintains the shape of the eye (A)</p> Signup and view all the answers

What condition is characterized by a clouding of the lens?

<p>Cataracts (C)</p> Signup and view all the answers

Which type of vision defect is caused by an eyeball that is too short?

<p>Hyperopia (D)</p> Signup and view all the answers

Where is the highest concentration of cones located within the eye?

<p>Fovea centralis (C)</p> Signup and view all the answers

What part of the eye has no photoreceptors and is known as the blind spot?

<p>Optic nerve (B)</p> Signup and view all the answers

What process involves the bending of light rays to focus an image on the retina?

<p>Refraction (B)</p> Signup and view all the answers

What type of hormones are primarily made from cholesterol?

<p>Steroids (A)</p> Signup and view all the answers

Which part of the brain processes visual information from the left visual field?

<p>Right occipital lobe (C)</p> Signup and view all the answers

How do endocrine glands primarily release their secretions?

<p>Directly into the bloodstream (D)</p> Signup and view all the answers

Which type of hormone receptor determines which tissues respond to a hormone?

<p>Hormone receptor (A)</p> Signup and view all the answers

What is the main difference between endocrine and exocrine glands?

<p>Endocrine glands secrete into the bloodstream, while exocrine glands secrete onto surfaces. (A)</p> Signup and view all the answers

What class of hormones is made from amino acids and hydrophilic in nature?

<p>Peptide hormones (D)</p> Signup and view all the answers

What hormone behavior is marked by a slow response time following a stimulus?

<p>Endocrine response (C)</p> Signup and view all the answers

Which of the following is a function of hormone receptors?

<p>To determine tissue response (D)</p> Signup and view all the answers

Flashcards

Autonomic Nervous System (ANS)

The part of the nervous system that controls involuntary functions like heart rate, digestion, and breathing.

Functions of the ANS

The ANS is responsible for adjusting the activity of glands, cardiac and smooth muscle, visceral organs, and blood vessels.

Involuntary Control of the ANS

The ANS operates involuntarily, meaning it works without conscious control.

Divisions of the ANS

The ANS has two main divisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS).

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Visceral Reflexes

A visceral reflex is an autonomic, involuntary, and stereotyped response to a stimulus involving visceral receptors and effectors.

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Homeostasis and the ANS

The primary function of the ANS is to maintain homeostasis by regulating internal body conditions like blood pressure, heart rate, and digestion.

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Sympathetic Nervous System (SNS)

The sympathetic nervous system (SNS) is responsible for the 'fight or flight' response, preparing the body for stressful situations.

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Parasympathetic Nervous System (PSNS)

The parasympathetic nervous system (PSNS) is responsible for the 'rest and digest' response, promoting relaxation and recovery.

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Taste (Gustation)

The sense of taste, also called gustation, is triggered by chemicals stimulating taste cells within taste buds.

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Taste Buds & Papillae

Taste buds are concentrated on papillae, the bumps on the tongue, with a total of about 14,000 taste buds per tongue.

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Five Basic Tastes

There are five basic tastes: salty, sweet, sour, bitter, and umami. Each taste is detected by specialized receptors on the taste cells.

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Taste Cell Mechanism

Taste cells are epithelial cells with chemoreceptors. They release neurotransmitters to sensory neurons in the facial (VII), glossopharyngeal (IX), and vagus (X) nerves.

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Smell (Olfaction)

The sense of smell, also called olfaction, is triggered by odorant molecules binding to receptors on olfactory sensory neurons.

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Olfactory Sensory Neurons

Olfactory sensory neurons are located in the olfactory mucosa within the upper nasal cavity. They are responsible for detecting odors by binding to specific odorant molecules.

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Olfactory Neuron Receptors

Each olfactory neuron expresses a single type of receptor out of 350 different types. This allows for the detection of a vast range of odors.

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Olfactory Pathway

The olfactory bulb receives olfactory information and relays it to the olfactory cortex, hypothalamus, and amygdala. Importantly, olfactory information does not pass through the thalamus.

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Sound Waves

The sensation of sound is due to the vibrations of molecules. These vibrations create waves of compression, where molecules push against each other, and the waves travel through a medium.

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Pitch

The frequency of a sound wave determines its pitch. High frequency waves correspond to high-pitched sounds, while low frequency waves produce low-pitched sounds.

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Loudness

The amplitude of a sound wave determines its loudness. Higher amplitude waves produce louder sounds, while smaller amplitude waves result in quieter sounds.

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Cochlea

The inner ear contains the cochlea, a fluid-filled structure that transforms vibrations into electrical signals. The cochlea's basilar membrane, with its hair cells, vibrates at a specific frequency depending on the sound's pitch.

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Hair Cells

Hair cells in the cochlea are mechanoreceptors that convert mechanical vibrations into electrochemical signals. When a sound wave causes the basilar membrane to vibrate, hair cells are bent against the tectorial membrane, leading to an influx of ions and the release of neurotransmitters.

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Vestibular Apparatus

The vestibular apparatus is a sensory system located in the inner ear that provides information about balance and head position. It consists of the vestibule (with the utricle and saccule) and the semicircular canals.

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Static Equilibrium

Static equilibrium refers to the sense of head orientation when stationary. It is detected by the utricle and saccule within the vestibule.

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Dynamic Equilibrium

Dynamic equilibrium involves sensing motion and acceleration. The utricle and saccule detect linear acceleration, while the semicircular canals detect angular acceleration.

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Conjunctiva

A clear, protective membrane that covers the front of the eye and the inner surface of the eyelids.

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Sclera

The white, fibrous outer layer of the eye that protects and maintains its shape.

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Choroid

The middle layer of the eye that contains blood vessels and nourishes the other layers.

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Iris

The colored part of the eye that controls the size of the pupil.

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Retina

The innermost layer of the eye that contains the light-sensitive photoreceptor cells.

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Fovea Centralis

The central part of the retina, responsible for sharp, detailed vision, with a high concentration of cone cells.

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Macula Lutea

A small region near the fovea centralis, responsible for color vision and fine detail.

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Phototransduction

The process by which light is converted into electrical signals that the brain can interpret as vision.

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Rhodopsin

A type of light-sensitive pigment found in the rods of the retina, responsible for vision in low-light conditions.

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Pigmented Epithelium

The layer of cells at the back of the eye that absorbs light and prevents it from reflecting back.

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Optic Chiasm

The point where the optic nerves from each eye cross over, allowing information from the left visual field to be processed by the right side of the brain, and vice versa.

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Visual Cortex

The part of the brain responsible for processing visual information, located in the back of the head.

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Light Adaptation

The process by which the body adjusts to changes in light intensity, allowing us to see clearly in both bright and dim environments.

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Hormone

A signaling molecule released by glands into the bloodstream, acting on distant target cells.

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Endocrine System

The system that regulates the body's internal environment by secreting hormones into the bloodstream.

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Glucagon

Hormone secreted by the alpha cells of the pancreas that increases blood glucose levels by promoting glycogen breakdown and gluconeogenesis in the liver.

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Insulin

Hormone secreted by the beta cells of the pancreas that lowers blood glucose levels by promoting glucose uptake and storage in cells, primarily via stimulating glycogen synthesis.

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Diabetes

A condition characterized by abnormally high blood glucose levels due to the body's inability to produce or effectively use insulin.

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Type 1 Diabetes

A type of diabetes characterized by autoimmune destruction of beta cells in the pancreas, leading to an absolute deficiency of insulin.

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Type 2 Diabetes

A type of diabetes characterized by insulin resistance, where body cells do not respond properly to insulin, and the pancreas may not produce enough insulin. Often associated with obesity.

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Study Notes

Autonomic Nervous System (ANS)

  • Self-governed
  • Part of the efferent division
  • Adjusts gland and smooth/cardiac muscle activity.
  • Involuntary and unconscious
  • Two divisions: sympathetic and parasympathetic
  • Visceral reflexes
    • Involuntary, stereotyped, slower than somatic reflexes.
    • Maintain homeostasis (example: Baroreflex regulates blood pressure)

Somatic vs. Autonomic Motor Control

  • Somatic:

    • Voluntary skeletal muscle control
    • One neuron from spinal cord to muscle
    • Only myelinated fibers
    • Acetylcholine (ACh) always excitatory

  • Autonomic:

    • Involuntary control of cardiac, smooth muscles, and glands
    • Two neurons from spinal cord
    • Myelinated preganglionic and unmyelinated postganglionic fibers

Sympathetic Nervous System (SNS)

  • "Fight or Flight" response
  • Activated by stress, trauma, danger, or exercise
  • Increases blood flow to skeletal muscles, heart rate, blood pressure, respiration rate, blood glucose
  • Dilates pupils, increases alertness, and reduces blood flow to digestive system.
  • Thoracolumbar division (T1-L2)
  • Short preganglionic fibers, long postganglionic fibers (sympathetic chain ganglia)
  • Some nerves have widespread effect

Parasympathetic Nervous System (PSNS)

  • "Rest and Digest"
  • Maintains normal body maintenance and calming effects.
  • Causes: reduced heart rate, constricted pupils, increased digestion, waste elimination, reproduction, glycogen synthesis
  • Craniosacral division (brainstem, S2-S4 spinal nerves)
  • Long preganglionic fibers, short postganglionic fibers (terminal ganglia)
  • Localized effect

Neurotransmitters of the ANS

  • Somatic: CNS to skeletal muscles, always excitatory, uses acetylcholine (Ach) + nicotinic receptors
  • Parasympathetic: CNS ganglion → smooth/cardiac muscle/glands, Ach + nicotinic receptors (excitatory), muscarinic receptors (inhibitory)
  • Sympathetic: CNS ganglion → smooth/cardiac muscle/glands, norepinephrine (NE) + adrenergic receptors (typically excitatory; some inhibitory)
  • Adrenal medulla secretes Epinephrine (Epi) and norepinephrine (Ne) directly into the bloodstream

Dual Innervation

  • Most organs receive both SNS and PSNS input.
  • Effects can be antagonistic (opposing, e.g., pupil dilation vs. constriction) or cooperative (unifying, e.g., salivation).

Senses (Afferent division)

  • Sensory receptors convert stimuli into nerve signals.
  • Sensation is awareness of a nerve signal reaching the brain.
  • Sensory receptors detect stimulus, convert it to an Action Potential (AP), and send it through sensory neurons
  • Sensory coding determines location, intensity, duration, and type of stimulus.
  • Receptive field = the area innervated by a sensory neuron.
  • Stimulus intensity = increased stimulus strength = increased neuron activation = higher frequency of APs
  • Sensory adaptation = firing rate of sensory neurons decreases or stops over time
    • Phasic receptors adapt rapidly (e.g., smell, hair movement).
    • Tonic receptors adapt slowly (e.g., body position, pain).
  • Stimulus type (modality) = different receptors designed for specific stimuli.
  • Labelled line code (specific pathways for specific sensory input)

Pain

  • Discomfort caused by injury or noxious stimulation leading to protective actions
  • Fast pain = myelinated fibers (sharp)
  • Slow pain = unmyelinated fibers (aching)
  • Referred pain = visceral pain perceived as originating from another area

Sensory Pathways

  • Ascending pathways transmit general sensory information.
  • They usually have three neurons (first, second, third-order neurons), and relay station in thalamus (somesthetic cortex)
  • Pain signals are sent to the limbic system and hypothalamus, proprioception to cerebellum, visceral to medulla oblongata

Taste (Gustation)

  • Chemicals stimulate taste cells.
  • Five basic tastes: salty, sweet, sour, bitter, umami
  • Taste perception involves combination of tastes + smell, temperature, and texture
  • Taste cells are epithelial cells with chemoreceptors
  • Taste cells replaced every 7-10 days

Smell (Olfaction)

  • Olfactory receptors in olfactory mucosa detect odors.
  • Olfactory cells have chemoreceptors for specific odorants.
  • Olfactory information does not go through the thalamus

Anatomy of the Ear

  • Outer ear: funnels sound to eardrum. Middle ear: ossicles transmit vibrations, eardrum to inner ear. Inner ear: balance (vestibule/semicircular ducts), hearing (cochlea)
  • Sound waves cause vibrations in the cochlea.
  • Hair cells convert vibrations into nerve impulses.
  • Pitch is determined by which part of the basilar membrane vibrates.

Equilibrium (Vestibular Apparatus)

  • Static equilibrium: head position (utricle and saccule).
  • Dynamic equilibrium: head movement (semicircular canals).
  • Otoliths increase the weight and inertia of the membranes.
  • Information travels to the vestibular cortex and other areas for balance control.

Vision

  • Six extrinsic eye muscles help move the eye
  • Components (3 layers): fibrous layer (sclera, cornea), vascular layer (choroid, iris, ciliary body), neural layer (retina, optic nerve)
  • Retina contains photoreceptors (rods and cones).
  • Image formation - involves reflection and refraction of light rays, accommodation adjusts the lens's shape
  • Defects: myopia (nearsightedness), hyperopia (farsightedness).
  • Visual pathways: left visual field to right brain, and vice versa

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Autonomic Nervous System Notes PDF

Description

Explore the intricacies of the Autonomic Nervous System (ANS), its functions, and how it contrasts with somatic motor control. This quiz will test your understanding of the sympathetic and parasympathetic divisions and their roles in regulating bodily functions and maintaining homeostasis.

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