CH 10: Muscle Tissue and Physiology

Overview of Muscle Types

Muscle tissue is essential for movement, posture, and various bodily functions. There are three main types of muscle tissue: skeletal, cardiac, and smooth, each with unique characteristics and functions.

• Skeletal muscle: Voluntary, striated, attached to bones, responsible for body movement.

• Cardiac muscle: Involuntary, striated, found only in the heart, responsible for pumping blood.

• Smooth muscle: Involuntary, non-striated, found in walls of hollow organs, responsible for movements like peristalsis.

Key characteristics shared by all muscle types:

• Excitability (ability to respond to stimuli)

• Contractility (ability to shorten)

• Extensibility (ability to stretch)

• Elasticity (ability to return to original shape)

Muscle Structure and Function

• Muscle fiber: The basic cellular unit of muscle tissue.

• Myofibril: Contractile threads found within muscle fibers.

• Filaments: Actin (thin) and myosin (thick) proteins that interact for contraction.

• Sarcomere: The functional unit of muscle contraction, defined by Z-lines.

Sliding Filament Model of Contraction

The sliding filament model explains how muscles contract at the molecular level.

• Steps:

  1. Excitation

  2. Excitation-contraction coupling

  3. Muscle contraction

  4. Muscle relaxation

• Role of calcium: Calcium ions bind to troponin, allowing actin-myosin interaction.

• ATP: Required for both contraction and relaxation.

Muscle Fatigue and Training

• Muscle fatigue: Decline in ability to generate force, often due to ATP depletion.

• Training: Different muscle fiber types (slow-twitch vs. fast-twitch) adapt to endurance or strength training.

Key Terms

• Synergistic muscles, Antagonistic muscles, Sarcomere, Muscle fiber, Myofibril, Fascicle, Troponin, Tropomyosin, Actin, Myosin, Neuromuscular junction, Acetylcholine, Acetylcholinesterase, Motor unit, Muscle twitch, Summation, Tetanus, Oxygen debt, Aerobic exercise, Resistance exercise, DOMS, Isotonic contractions, Isometric contractions, Myoglobin

CH 11: Nervous System Fundamentals

Overview of the Nervous System

The nervous system coordinates body activities through electrical and chemical signals. It is divided into the central nervous system (CNS) and peripheral nervous system (PNS).

• Primary divisions: CNS (brain and spinal cord), PNS (nerves outside CNS)

• Neuroglia: Support cells in the nervous system (e.g., astrocytes, oligodendrocytes, Schwann cells)

Neurons and Their Functions

• Sensory neurons: Transmit impulses from receptors to CNS

• Interneurons: Connect neurons within CNS

• Motor neurons: Transmit impulses from CNS to effectors

Neuron Structure

• Dendrite: Receives signals

• Axon: Transmits signals

• Myelin sheath: Insulates axon, increases speed of conduction

• Schwann cell: Produces myelin in PNS

Action Potentials and Synapses

• Action potential: Rapid change in membrane potential that travels along axon

• Threshold: Minimum stimulus needed to trigger action potential

• Synapse: Junction between neurons for signal transmission

• Neurotransmitters: Chemical messengers (e.g., acetylcholine, dopamine, serotonin, GABA)

Disorders and Diseases

• Multiple Sclerosis (MS): Demyelination of CNS neurons

• Myasthenia Gravis: Autoimmune disorder affecting neuromuscular junction

• Parkinson's Disease: Degeneration of dopamine-producing neurons

• Alzheimer's Disease: Progressive neurodegeneration affecting memory

Key Terms

• Neurons, Neuroglia, Myelin sheath, Sensory neuron, Interneuron, Motor neuron, Dendrite, Axon, Resting potential, Action potential, Neurotransmitter, Excitatory synapse, EPSP

CH 12: Central Nervous System (CNS)

Functional Arrangement and Protection

The CNS consists of the brain and spinal cord, protected by meninges and cerebrospinal fluid (CSF).

• Meninges: Dura mater, arachnoid mater, pia mater

• CSF: Cushions and nourishes CNS

• Blood-brain barrier: Regulates passage of substances into CNS

Brain Regions and Functions

• Cerebrum: Higher cognitive functions

• Cerebellum: Coordination and balance

• Brainstem: Vital functions (medulla, pons, midbrain)

• Thalamus: Sensory relay

• Hypothalamus: Homeostasis, hormone regulation

• Limbic system: Emotion and memory

Gray Matter vs. White Matter

• Gray matter: Neuron cell bodies

• White matter: Myelinated axons

Homeostasis and CNS Tracts

• Vital functions: Breathing, heart rate, temperature regulation

• Tracts: Bundles of axons transmitting signals

Key Terms

• CNS, PNS, Ganglia, Meninges, Dura mater, Pia mater, Arachnoid layer, Cerebrum, Cerebral cortex, White matter, Gray matter, Thalamus, Hypothalamus, Pons, Medulla, Cerebellum, Limbic system, Hippocampus, Short-term memory, Long-term memory, Beta waves, Theta waves, Delta waves, Fever

CH 13: Peripheral Nervous System (PNS) and Reflexes

PNS Functions and Structure

The PNS connects the CNS to limbs and organs, facilitating sensory and motor functions.

• Cranial nerves: 12 pairs, serve head and neck

• Spinal nerves: 31 pairs, serve body below head

• Nerve plexi: Networks of intersecting nerves

Sensory Receptors and Reflexes

• Receptors: Detect stimuli (mechanoreceptors, thermoreceptors, nociceptors)

• Reflex arc: Pathway for reflex action (receptor, sensory neuron, integration center, motor neuron, effector)

• Basic reflexes: Stretch, withdrawal, crossed-extension, cranial, Golgi tendon

Key Terms

• Somatic sensory, Visceral sensory, Somatic motor, Autonomic motor, Parasympathetic, Sympathetic, Cranial nerves, Spinal nerves, Trigeminal neuralgia, Bell's palsy, Receptor potential, Sensory receptor adaptation, Mechanoreceptors, Thermoreceptors, Nociceptors, Photoreceptors, Merkel cell fibers, Meissner's corpuscles, Ruffini corpuscles, Pacinian corpuscles, Hair follicle receptors, Receptive field, Referred pain, Dermatome, Alpha-motor neurons, Gamma-motor neurons, Upper motor neurons, Lower motor neurons, Muscle spindles, Golgi tendon organs, Monosynaptic reflex, Polysynaptic reflex, Stretch reflex, Withdrawal reflex, Crossed-extension reflex, Gag reflex, Corneal blink reflex, Babinski sign, Plantar reflex, ALS

CH 14: Autonomic Nervous System (ANS)

ANS Functions and Divisions

The ANS regulates involuntary functions such as heart rate, digestion, and respiratory rate. It is divided into sympathetic and parasympathetic systems.

• Sympathetic: "Fight or flight" responses

• Parasympathetic: "Rest and digest" responses

Neurotransmitters and Receptors

• Neurotransmitters: Acetylcholine, norepinephrine

• Receptors: Cholinergic (muscarinic, nicotinic), Adrenergic (alpha, beta)

Key Terms

• Visceral reflex arc, Preganglionic neuron, Sympathetic chain ganglia, Acetylcholine, Epinephrine/norepinephrine, Cholinergic receptors, Adrenergic receptors, Alpha-1, Alpha-2, Beta-1, Beta-2, Beta-3 receptors

CH 16: Endocrine System

Endocrine and Exocrine Glands

The endocrine system regulates body functions through hormones released into the bloodstream. Exocrine glands secrete substances through ducts.

• Endocrine glands: Pituitary, thyroid, adrenal, pancreas, etc.

• Exocrine glands: Sweat, salivary, mammary glands

Hormone Mechanisms and Regulation

• Lipid-soluble hormones: Pass through cell membranes, act on intracellular receptors

• Water-soluble hormones: Bind to membrane receptors, use second messenger systems

• Negative feedback: Maintains homeostasis by inhibiting further hormone release

• Second messenger system: Often involves cAMP or Ca2+ as intracellular signals

Major Hormones and Functions

• Growth hormone (GH): Stimulates growth and cell reproduction

• Prolactin (PRL): Stimulates milk production

• Thyroid stimulating hormone (TSH): Stimulates thyroid hormone release

• Adrenocorticotropic hormone (ACTH): Stimulates adrenal cortex

• Follicle stimulating hormone (FSH): Stimulates gamete production

• Luteinizing hormone (LH): Stimulates sex hormone production

• Antidiuretic hormone (ADH): Regulates water balance

• Insulin: Lowers blood glucose

• Glucagon: Raises blood glucose

• Leptin, Erythropoietin, Melatonin: Various regulatory functions

Hormonal Disorders

• Diabetes mellitus: Impaired insulin production or response

• Grave's disease: Hyperthyroidism

• Cushing's syndrome: Excess cortisol

• Addison's disease: Adrenal insufficiency

Key Terms

• Endocrine gland, Exocrine gland, Hormone, Target cells, Lipid-soluble hormone, Water-soluble hormone, First messenger, Second messenger, Positive feedback, Negative feedback, Pituitary, Hypothalamus, Neurosecretory cell, Releasing hormone, Inhibiting hormone, Growth hormone, Prolactin, Thyroid stimulating hormone, Adrenocorticotropic hormone, Follicle stimulating hormone, Luteinizing hormone, Oxytocin, Thyroid gland, Thyroid hormone, Cretinism, Gigantism, Grave's disease, Calcitonin, Parafollicular cells, Parathyroid hormone, Adrenal cortex, Adrenal medulla, Glucocorticoids, Mineralocorticoids, Androgens, Estrogens, Aldosterone, Epinephrine, Norepinephrine, Addison's disease, Pancreatic islets, Insulin, Glucagon, Thymus, Thymosin/Thymopoietin, Pineal gland, Melatonin, EPO

Tables

Comparison of Muscle Types

Major Neurotransmitters and Functions

Hormone Types and Mechanisms

Key Equations

• Resting membrane potential: Additional info: Actual equation is more complex, involving Na+ and Cl- ions.

• ATP hydrolysis (muscle contraction):

• Hormone-receptor binding (general):