physio pt 2
Anterior Pituitary
"Master endocrine gland" because many of the numerous hormones it produces regulate the activity of other endocrine glands •
thin filaments
- composed mostly of the protein actin
Thick filaments
- composed mostly of the protein myosin
Zona fasciculata
-Produce glucocorticoids
Zona reticularis
-Produce small amounts of adrenal sex hormones, or gonadocorticoids
Endocrine glands
-organs that secretes hormones
1. Release of acetylcholine 2. Activation of ACh receptors 3. Production of muscle action potential
A nerve impulse (nerve action potential) elicits a muscle action potential in the following way:
Electrical excitability
A property of both muscle and nerve cells
1. RESTING MEMBRANE POTENTIAL 2. TRIGGER OF NERVE IMPULSE 3. TRESHOLD REACHED FOR DEPOLARIZATION 4. TRESHOLD REACHED FOR REPOLARIZATION 5. RESTING MEMBRANE POTENTIAL **NO HYPERPOLARIZATION
ACTION POTENTIAL:
Primary motor cortex Motor areas
Allow us to consciously control the precise or skilled voluntary movements of our skeletal muscle
Growth hormone (GH) • Thyroid-stimulating hormone (TSH) • Adrenocorticotropic hormone (ACTH) • Follicle-stimulating hormone (FSH) • Luteinizing hormone (LH) • Prolactin (PRL)
Anterior Pituitary
Estrogen
Believed to lower blood levels of cholesterol and triglyceride
Gonadocorticoids (Adrenal Sex Hormones)
Contribute to growth of axillary and pubic hairs
Zona glomerulosa - Produce mineralocorticoids Zona fasciculata -Produce glucocorticoids Zona reticularis -Produce small amounts of adrenal sex hormones, or gonadocorticoids
Cortical cells are arranged in three layers or zones:
somatic motor neuron
Each ---- has a threadlike axon that extends from the brain or spinal cord to a group of skeletal muscle fibers
Producing body movements Stabilizing body positions Storing and moving substances within the body Generating heat
FUNCTIONS OD MUSCULAR SYSTEM
• Chemical composition and volume of internal environment (interstitial fluid) • Metabolism and energy balance • Contraction of smooth and cardiac muscle fibers • Glandular secretions • Some immune system activities • Control growth and development • Regulate operation of reproductive systems • Help establish circadian rhythms
Function of hormones
Aldosterone
Helps adjust blood pressure and blood volume
Posterior pituitary HYPOTHALAMUS AND PITUITARY GLAND
Hormone-storage area and not a true endocrine gland that manufactures hormone
Thyroid hormone (TH)
Is actually two iodine-containing amine hormones:
Cerebral Cortex
Is the "executive suite" of the nervous system, where our conscious mind is found
Contractility
Is the ability of muscular tissue to contract forcefully when stimulated by an action potential
Gonadocorticoids (Adrenal Sex Hormones)
Largely account for the estrogens produced after menopause when ovarian estrogens are no longer produced
Primary motor cortex Motor areas
Located in the precentral gyrus of the frontal lobe of each hemisphere
1. Electrical excitability 2. Contractility 3. Extensibility 4. Elasticity
Properties of Muscular Tissues
hormones
Released in one part of the body but regulates the activity of cells in other parts of the body
inside target cells
The receptors for lipid soluble hormones are located
600
There are more than --- muscles in the human body
The Contraction Cycle
There, they bind to troponin which moves tropomyosin away from the myosin-binding sites on actin
Aspirin
These people may bruise easily because blood clotting has been impaired
Gonadocorticoids (Adrenal Sex Hormones)
They promote libido (sex drive) and are converted into estrogens (feminizing sex steroids) by other body tissue
Adenosine
Sleep-promoting chemical that is produced in the brain during waking hours
Once the binding sites are "free," the contraction cycle begin
The Contraction Cycle
Gonadocorticoids (Adrenal Sex Hormones)
The amount of androgens by the adrenal cortex is insignificant compared with the amounts made by the gonads during late puberty and adulthood
axon
The end of the motor neuron, called the ---terminal, divides into a cluster of synaptic end bulbs the neural part of the NMJ
Thyroid gland
The largest pure endocrine gland in the body
somatic motorneurons
The neurons that stimulate skeletal muscle to contract are
Gonadocorticoids (Adrenal Sex Hormones)
a weak male sex hormone
Both thin and thick filaments
are directly involved in the contractile process
Muscle contraction
begins with a nerve impulse that releases acetylcholine at the neuromuscular junction.
motor sensory association
cerebral cortex functional areas:
Aspirin
inhibits the synthesis of prostaglandins involved in pain mechanisms and usually relieves the pain
synapse
is a region where communication occurs somatic motor neuron and a muscle fiber
structural protein
keep the thick and thin filaments in the proper alignment, give the myofibril elasticity and extensibility
Endocannabinoids
lipid-based retrograde neurotransmitters that bind to cannabinoid receptors (CBRs)
Cortisol
mobilizes fatty acids from adipose tissue and encourages their increased use for energy
Adrenal glands
pyramid-shaped organs perched atop the kidneys
Oxytocin
receptors in the uterus peaks near the end of pregnancy
Thyroid gland
stores enough colloid to provide normal levels of hormone for two to three months
tropomyosin
strands in turn are held in place by troponin molecule
Tetrahydrocannabinol THC
the active ingredient in marijuana, actat the same receptor alongs with Endocanabinoids
Caffeine
well-known stimulatory effects result from blocking the adenosine receptors
Contractile proteins
which generate force during contraction
regulatory proteins
which help switch the contraction process on and off
sarcoplasmic reticulum or SR
• A fluid-filled system of membranous sacs called the --- encircles each myofibril
Prostaglandins
• A local hormone
Broca's area
• A special motor speech area that directs the muscles involved in speech production
Oxytocin
• A strong stimulant of uterine contraction
Antidiuretic Hormone (ADH)
• ADH targets the kidney tubules and respond by reabsorbing more water from the forming urine and returning it to the bloodstream
Thyroid gland
• Ability to store its hormone extracellularly and in large quantities
Myofibril
• About 2 um in diameter and extend the entire length of a muscle fiber
Local hormones
• Act locally on neighboring cells (paracrines) or on the same cell that secreted them (autocrines) without first entering the bloodstream
Oxytocin
• Also acts as the hormonal trigger for milk ejection (the "letdown" reflex) in women whose breasts are producing milk in response to prolactin
Cerebrospinal Fluid (CSF)
• Also protects the brain and spinal cord from blows and other trauma
Cerebral Cortex
• Although only 2-4 mm (about 1/8 inch) thick, it accounts for roughly 40% of total brain mass
Actin
• Anchored to Z discs
Generating heat thermogenesis
• As muscular tissue contracts, it produces heat, a process known as ---. Much of the heat generated by muscle is used to maintain normal body temperature
The Contraction Cycle
• At the onset of contraction, the sarcoplasmic reticulum releases calcium ions (Ca2+) into the sarcoplasm
Sarcolemma
• Beneath is the location of multiple nuclei of a skeletal muscle fiber
Cerebrospinal Fluid (CSF)
• By floating the jellylike brain, the CSF effectively reduces brain weight by 97%and prevents the delicate brain from crushing under its own weight
Broca's area
• Considered to be present in one hemisphere only (usually the left)
Synergistic muscles
• Contract and stabilize the intermediate joints
ENDOCRINE SYSTEM
• Controls body activities by releasing mediators, called hormones
Estrogen
• Deposition of fat subcutaneously in the hips and thighs
Antidiuretic Hormone (ADH)
• Drinking alcoholic beverages inhibits ADH secretion and causes copious urine output
Storing and moving substances within the body
• E.g. Temporary storage of food in the stomach or urine in the urinary bladder is possible because smooth muscle sphincters close off the outlets of these organs
Parathyroid gland
• Each has a mass of about 40 mg (0.04 g)
hormones
• Enter via interstitial fluid and then the bloodstream
Parathyroid hormone (PTH)
• Falling blood Ca2+ levels trigger PTH release, and rising blood Ca2+ levels inhibit its release
Cerebrospinal Fluid (CSF)
• Forms a liquid cushion that gives buoyancy to CNS structures
Cerebrospinal Fluid (CSF)
• Found in and around the brain and spinal cord
Melatonin
• Greatest during darkness and decreases when light enters the eye and the retina signals the hypothalamus
Testosterone
• Growth (protein synthesis) of the skeletal muscles
Estrogen
• Growth in height stop
Testosterone
• Growth of all the reproductive organs • Growth of facial and body hair
Estrogen
• Growth of the duct system of the mammary glands
Testosterone
• Growth of the larynx and deepening of the voice
Estrogen
• Growth of the uterus
Glucocorticoids
• Help the body adapt to intermittent food intake by keeping blood glucose levels fairly constant
Antidiuretic Hormone (ADH)
• Helping the body avoid dehydration and water overload
Premotor cortex
• Helps plan movements
Titin
• Helps the sarcomere return to its resting length after a muscle has contracted or been stretched
Hormone receptors
• Hormones affects only specific target cells by chemically binding to specific protein receptors
Antidiuretic Hormone (ADH)
• Hypothalamic neurons called osmoreceptors continually monitor the solute concentration of the blood
Cerebrospinal Fluid (CSF)
• In adults, the total CSF volume of about 150 ml (about half a cup) is replaced every 8 hours or so
Tropomyosin and troponin
• In relaxed muscle, myosin is blocked from binding to actin because strands of tropomyosin cover the myosin-binding sites on actin
Glucocorticoids
• Include cortisol (hydrocortisone), cortisone, and corticosterone
Adrenal medulla
• Increase heart rate and force of contraction causing output of the heart, which increases blood pressure
Thyroid hormone (TH) Effects of thyroid hormone include:
• Increasing basal metabolic rate and body heat production
Adenosine
• Increasing levels induces sleep
Actin
• Individual actin molecules join to form an actin filament that is twisted into a helix
Glucocorticoids
• Influence the energy metabolism of most body cells and help us resist stressors
thousands of molecules of acetylcholine (ACh),
• Inside each synaptic vesicle are --- the neurotransmitter released at the NMJ
Endocannabinoids
• Involved in regulating physiological and cognitive processes
Extensibility
• Is the ability of muscular tissue to stretch, within limits, without being damaged
Electrical excitability
• Is the ability to respond to certain stimuli by producing electrical signals called action potentials (impulses)
Cerebral Cortex
• It enables us to be aware of ourselves and our sensations, to communicate, remember, understand, and initiate voluntary movements
Posterior pituitary HYPOTHALAMUS AND PITUITARY GLAND
• It releases neurohormones (hormones secreted by neurons) received ready-made from the hypothalamus
Premotor cortex
• Just anterior to the precentral gyrus in the frontal lobe
Broca's area
• Lies anterior to the inferior region of the premotor area
Frontal eye field
• Located partially in and anterior to the premotor cortex and superior to Broca's area
Prostaglandins
• Made by virtually all cells from their cell membranes
Myosin
• Main component of thick filaments and functions as a motor protein in all three types of muscle tissue
Actin
• Main protein component of thin filament
Prostaglandins
• Mainly involved in inflammation, pain mechanisms, blood clotting, vasoconstriction and vasodilation
Thyroid hormone (TH) Effects of thyroid hormone include:
• Maintaining blood pressure
Aldosterone
• Major mineralocorticoid
Circulating hormones
• Most endocrine hormones
Myosin
• Motor proteins pull various cellular structures to achieve movement by converting the chemical energy in ATP to the mechanical energy of motion, that is,the production of force
Somatic motor neurons
• Neurons that stimulate skeletal muscle fibers to contract
Actin
• On each actin molecule is a myosin- binding site, where a myosin head can attach
Posterior pituitary HYPOTHALAMUS AND PITUITARY GLAND
• Oxytocin and Antidiuretic Hormone (ADH
Parathyroid gland
• Partially embedded in the posterior surface of the lateral lobes of the thyroid gland
Sarcolemma
• Plasma membrane of a muscle cell
Melatonin
• Produced by the pineal gland
Estrogen
• Promotes the maturation of the ovum
Progesterone
• Promotes the storage of glycogen and the further growth of blood vessels in the endometrium, which thus becomes a potential placenta
Aldosterone
• Regulate the electrolyte (mineral salt) concentrations in extracellular fluids, particularly of Na+ and K+
Thyroid hormone (TH) Effects of thyroid hormone include:
• Regulating tissue growth and development
Producing body movements
• Rely on the integrated functioning of skeletal muscles, bones, and joints.
Premotor cortex
• Selects and sequences basic motor movements into more complex tasks, such as playing a musical instrument or typing
Aldosterone
• Sets the resting membrane potential of all cells and determines how easily action potentials are generated in nerve and muscle
Oxytocin
• Significantly higher amounts during childbirth and in nursing women
Stabilizing body positions
• Skeletal muscle contractions stabilize joints and help maintain body positions, such as standing or sitting
The Sliding Filament Mechanism
• States that during contraction the thin flaments slide past the thick ones so that the actin and myosin flaments overlap to a greater degree
Estrogen
• Stimulates development of female secondary sex characteristics
Estrogen
• Stimulates the growth of blood vessels in the endometrium in preparation for a possible fertilized egg
Antidiuretic Hormone (ADH)
• Substance that inhibits or prevents urine formation
Adrenal medulla
• Synthesize the catecholamines epinephrine and norepinephrine (NE)
The Adrenal Cortex
• Synthesizes well over two dozen steroid hormones, collectively called corticosteroids
Myofibril
• The contractile organelles of skeletal muscle
part of the plasma membrane of target cells
• The receptors for water-soluble hormones are
Parathyroid hormone (PTH)
• The single most important hormone controlling calcium balance in the blood • Control of Ca2+ is essential for so many functions, including transmission of nerve impulses, muscle contraction, and blood clotting
Titin
• The third most plentiful protein in skeletal muscle (after actin and myosin)
transverse (T) tubules Sarcolemma
• Tiny invaginations of the sarcolemma, called ----- , tunnel in from the surface toward the center of each muscle fiber
Synergistic muscles
• To prevent unwanted movements at intermediate joint
Progesterone
• When an ovum was released, the corpus luteum and begins to secrete progesterone in addition to estrogen
Sarcomeres
• basic functional units of a myofibri
Adrenal medulla
• catecholamines secreted in stress situations and help prepare the body for "fight or flight."
Elasticity
• is the ability of muscular tissue to return to its original length and shape after contraction or extension
Circulating hormones
•They pass from the secretory cells that make them into interstitial fluid and then into the blood
Down regulation vs up-regulation
- If a hormone is present in excess, the number of target-cell receptors may decrease
Zona glomerulosa
- Produce mineralocorticoids
Testosterone
- Promotes maturation of sperm in the testes
tendon
Most of the muscles are attached to the bones of the skeleton by
Antagonistic Muscles Synergistic muscles
Muscle arrangement
Antagonistic Muscles
Muscles that have opposing or opposite functions • Biceps branchii • Triceps branchii
contractile regulatory structural
Myofibrils are built from three kinds of proteins:
Melatonin
Stimulates the onset of sleep and increases its duration
synaptic vesicles
Suspended in the cytosol within each synaptic end bulb are hundreds of membrane-enclosed sacs called --