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 --