11 - Endocrine & Musculoskeletal

8/3/2019 11 - Endocrine & Musculoskeletal

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I. Hormone overview

II. Hypothalamus &

Pituitary

III. Thyroid

IV. Parathyroid

V. Pancreas

VI. Ovaries & Testes

VII. Adrenals

Lecture Outline Ch. 46: Endocrine System


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Hormones in Animals

Hormones influence growth, development, mood


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Types of Glands:

Sweat glands

Salivary glands

Mammary glands

2) Endocrine Glands:

Release substances within the body via bloodstream

Ductless

1) Exocrine Glands:

Release substances outside

the body via ducts

Hormones in Animals


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ovarytestis

Pituitary gland

Hypothalamus

Pancreas islet cells

Adrenal glands

(one at each kidney)

Thymus gland

Thyroid gland

Pineal gland

Parathyroid glands (on posteriorsurface of thyroid gland)

Heart

Kidneys

Digestive tract

Gonads

Hormones in Animals


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Hormones released in response to stimuli

Travel through the circulatory system to reach target cells

A cell is affected only if it has receptors specific to that hormone

Most hormones are controlled by negative feedback,which inhibits further release

In a few cases, positive feedback is used to amplifyhormone levels

Hormones in Animals


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General Classes of Hormones:

Hormones in Animals


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Hypothalamus:

Region of brain

Make and store

peptide hormones

Collection of

neurosecretory cells

Hypothalamus & Pituitary

Secretes to anterior

pituitary via portal system


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Pituitary Gland:

Pea-sized gland;

hangs from hypothalamus

Release hormones

Controlled by hypothalamus:

Inhibit hormones

Hypothalamus & Pituitary

hypothalamus

pituitary(anteriorlobe)

pituitary(posterior lobe)

Master regulation/coordination center


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Pituitary

Anterior Pituitary (adenohypophysis):

True gland

Follicle-stimulating Hormone (FSH) - egg / sperm production

Luteinizing Hormone (LH) - sex hormone secretion

Thyroid-stimulating Hormone (TSH) - hormones from thyroid

Adrenocorticotropic Hormone (ACTH) - hormones from adrenal cortex

Prolactin - mammary gland development

Melanocyte-stimulating Hormone (MSH) - synthesis of melanin (skin pigment)

Growth Hormone (GH) - growth of body cells

Releases hormones that affect other glands

Indirect (stimulate other glands)

Direct (stimulate tissues)


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Goiters are caused

by a lack of iodine

in the diet

Pituitary


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Pituitary

Tom Thumb

(Charles Stratton)

Robert Wadlow

811


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Pituitary

Posterior Pituitary (Neurohypophysis):

Extension of cells in hypothalamus Releases two hormones

Contains neurosecretory cells

with bodies in hypothalamus

Antidiuretic Hormone (ADH)

water conservation (kidneys)

Oxytocin

Contraction of uterus muscles

Milk letdown reflex

Maternal behaviors

hypothalamus

pituitary(posterior lobe)


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Thyroid:

Secretes Thyroxine

(T4 - Amino Acid Hormone):

Controlled by TSH from ant. pit. (Thyroid-Stimulating Hormone)

Regulates metabolism & growth

Iodine required for

T4 production

Thyroid Gland

larynx

trachea

parathyroidglands

esophagusthyroid gland

Wraps around the front of the larynx in the neck


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Parathyroid:

Secretes Parathyroid

hormone (PTH)

Regulates blood calcium levels

Imbedded in thyroid gland

Parathyroid Gland

larynx

trachea

parathyroidglands

esophagus

thyroid gland

releasePTH

calcium releasefrom bone

normal blood

calcium

low blood calcium


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Pancreas:

Both exocrine and endocrine:

Pancreas

Exocrine = Digestive enzymes

(small intestine)

Endocrine = Hormones

regulating blood sugar

Insulin

Reduces blood sugar

(cells uptake glucose)

Glucagon

Increases blood sugar

(cells release glucose)

Type I Diabetes: lack cells

Type II Diabetes: low #s

insulin receptors


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Sex Organs:

1) Ovaries (Female):

Estrogen / Progesterone(steroid hormones)

2) Testes (Male):

Testosterone (steroid hormone)

Follicle-stimulating Hormone Luteinizing Hormone

Controlled by FSH and LH from ant. pit.

Ovaries & Testes

Functions:

Early development (brain development)

Puberty

Menstrual cycle; pregnancy


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1) Adrenal Medulla (center of gland)

Epinephrine (Adrenaline)/Norepinephrine (Amino acid hormones)

Prepare for fight or flight

Controlled by nervous system

Adrenal Glands

kidney

Adrenal medulla secretes

epinephrine and norepinephrine.

adrenal gland


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2) Adrenal Cortex (outside of gland)

Glucocorticoids (Steroid hormones) Released in stressful situations

Controlled by ACTH (ant. pit.)

Testosterone

Adrenal Glands

kidney

Adrenal cortex

glucocorticoids,

aldosterone, and

testosterone.

adrenal gland

Congenital adrenal

hyperplasia (CAH)


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1) Most Cells in Body

Prostaglandins (Fatty Acid Hormones): Target = Nearby cells

Function is varied (Inflammation; Uterine contractors)

Ibuprofen

2) Pineal Gland

Melatonin (Amino Acid Hormone): Regulate sleep/wake cycle; reproductive cycle (non-humans)

3) Thymus

Thymosin: Stimulates white blood cell production

4) Kidneys

Erythropoietin: Regulates red blood cell production

Other Sources of Hormones


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5) Adipose Cells:

Leptin: Regulates body fat

Other Sources of Hormones

Leptin tells body

how much fat is

stored anddecreases appetite

Link between

obesity and leptin

sensitivity

leptin-deficient mouse normal mouse


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ovarytestis

Pituitary glandanterior pituitary:

ACTH, TSH, GH, PRL, FSH, LH, and MSHposterior pituitary:

releases oxytocin and ADH

Hypothalamus

produces ADH and oxytocin, regulatory

hormones for anterior pituitary

Pancreas islet cells

insulin, glucagon

Adrenal glands (one at each kidney)medulla:

epinephrine, norepinephrine

cortex:glucocorticoids (cortisol), aldosterone,testosterone

Thymus gland

(atrophies during adulthood)

Thyroid gland

thyroxine, calcitonin

Pineal gland

melatonin

Parathyroid glands (on posteriorsurface of thyroid gland)parathyroid hormone

Kidneyserythropoietin

Gonads

testes (male):

androgens, especially testosteroneovaries (female):

estrogens, progesterone

A Good Slide to Know


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Self-Check:

PituitaryAnterior Posterior

GonadsThyroid

Adrenal

Medulla

Adrenal

CortexPancreas

Kidney


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What allows animal movement in response to stimuli?

Thought Questions:


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I. Skeletal MusclesA. Structure

B. Contraction

C. Nerve Input

Lecture OutlineLecture Outline Ch.47: Muscular & SkeletalCh.47: Muscular & Skeletal

II. Skeletal Systems

III. Vertebrate Skeletons

A. Support

B. Protection

C. Movement

D. Joints


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Muscular and skeletal systems

Muscles power

movement bycontracting

Bones provide

framework formuscles


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Muscle Tissue (Muscle = little mouse):

Exerts force by

contracting

Chemical energy (ATP) Mechanical EnergyTransformation

Muscles

Movement due to actinmicrofilaments andmyosin strands

Slide past one another,

change cell shape


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Types of Muscle Tissue:

Skeletal Muscle Cardiac Muscle Smooth Muscle

Striated Striated Not Striated

Voluntary Involuntary Involuntary

Appearance

Control

FunctionSkeletal

Movement

Pump BloodMove Substances

Through Hollow Tubes

Muscles


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connective tissuetendon (to bone)

Skeletal muscle

Muscle fiber(muscle cell)

Myofibril(contains thin sand thick

filaments)

bundle ofmuscle cells

nerve andblood vessels

Skeletal Muscles

Humans > 700 unique skeletal muscles

Muscle connected to bones by tendons


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Cross section of fiber

m

usclefiber

T tubules

plasmamembrane

myofibril

sarcoplasmicreticulum

Skeletal Muscles

- Each muscle cell runs lengthof muscle

- Multinucleate

- Made up of myofibrils

Contractile cylinders of actinand myosin

- Each myofibril surrounded bysarcoplasmic reticulum

- Fluid with high calcium levels

- T-tubules in plasma membrane relay signals


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Myofibril

myofibril

sarcomere

thick filamentthin filament

Z lines

Skeletal Muscles

Myofibrils of thickand thin filaments.

Each filament is madeof protein strands.

Filaments arranged in sarcomeres

Separated by Z-lines of fibrous protein


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Thick and thin filaments

tropomyosin

thin filament

thick filament(myosin)

myosin heads

accessoryproteins

troponin

actin

Skeletal Muscles

Thick filaments: made mostly of myosin, havesmall moveable heads

Thin filaments: primarily actin, have points towhich the myosin heads temporarily attach


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binding sites

thick filament

thin filament

ATP

ADP

myosin head

Skeletal Muscles

Each actin subunit has

binding site for myosinhead

Contraction exposes bindingsites, allowing filaments tobind to one another

Myosin heads thenrepeatedly bend, pull,release, and reattach(using ATP-energy)


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Sliding filaments shorten each sarcomere

Skeletal Muscles


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Neuromuscular junctions between axons and fibers

All or nothing response:

Skeletal muscle excited

All sarcomeres respond

Skeletal Muscles

postsynaptic

membrane

axon of motor neuron

synaptic terminalsynaptic vesicles


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Strength of Muscle Contractionp # of Fibers Stimulated

Motor Unit:A single motor

neuron and all the

muscle fibers

innervated by it

Skeletal Muscles


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Action potential travels through T-channels and opensCa++ channels in sarcoplasmic reticulum

These ions allow binding of thin and thick fibers

Ca++ is pumped back out after action potential ends

Unless youre dead

Skeletal Muscles


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You cannot add

muscle fibers

You can add moremyofibrils

Skeletal Muscles

muscle

Muscle fiber(muscle cell)

Myofibril

bundle ofmuscle cells


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Slow-twitch fibers:

Lots of myoglobin (provides O2) and mitochondria.Fast-twitch fibers:

Less myoglobin and mitochondria

More able to use glycolysis to quickly produce ATP

Different people (& muscles) different ratios of two fibers.

80% slow twitch

80% fast twitch

50% slow

50% fast

Skeletal Muscles


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A supporting framework for the body

Skeletal System


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Hydrostatic skeleton

Fluid provides support

Muscles contract and move fluid

Skeletal System


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Exoskeleton

Hard shells cover outside of body

Muscles contract and move frameat joints

Skeletal System


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Endoskeleton

Internal framework - least commonskeleton type

Muscles contract and move frame atjoints

Skeletal System


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Support body

Protect fragile organsAllow movement

Produce blood cells

Store minerals

Transmit vibrations (hearing)

Vertebrate Skeletons


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Bodily Support

Axial skeleton- main body axis

Appendicular skeleton- appendages and supporting structures



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Protection

Skull- brainVertebral column- nerve cord

Ribcage soft internal organs



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Movement

Three skeletal connective tissuesCartilage- tough, but flexible

Skeletal development

Cushioning joints

Ligaments- toughConnect bones at joints

Bone- tough and rigid


bone

cartilage


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Bone = hardened by deposits of calcium phosphate

Compact bone (exterior) is dense and strongSpongy bone (interior) is lightweight and porous


collagenmatrixcollagenmatrix

osteon

cartilage

compactbone

spongybone

(containsmarrow)

chondrocyteschondrocytes

osteocytes

capillary

central

canal


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Blood cell production

Red blood cells, whiteblood cells, platelets

Produced by bone marrow


Leukemia: cancer of the bone

marrow, leads to decreasedblood cells

Mineral storage

Bones store and releasecalcium and phosphorous tomaintain constantconcentrations


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Bone cells work together

Osteoclasts- bone dissolving cells

Dissolve cartilage

Osteoblasts- bone forming cells

Replace cartilage with bone

Osteocytes- mature bone cells

Cannot produce more bone,but can remodel it



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Bone remodeling

Can alter skeletal shape in response to useOsteoclasts create channels invaded by

capillaries and osteoblasts to formnew bone

Osteoporosis is when activity ofosteoclasts outstrips osteoblasts


Normal bone section Osteoporosis


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Movement of bones

Joints are where two bones meetLubricated by cartilage

Attached by ligaments

Muscles are attached to bone oneither side of the joint

Attached by tendons

Ligaments

Origin - attachment to still bone

Insertion - attachment to movingbone



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MovementAntagonistic muscle pairs pull the

bone in opposite directs whenthey contract

Flexor muscle bends the jointExtensor muscle straightens it



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JointsImmovable- joints do not move (skull)


Ball & Socket rotational movement in alldirections (hip, shoulder)

Hinge extend or retract an appendage in onedirection (knee)

Gliding permit sliding of two surfaces (spine)

Combination utilize more than one of above (jaw)


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Lecture 11 Summary1. Overview (Ch. 46)

- Gland types

- Classes of hormones2. Hormones (Ch. 46)

- Hypothalamus & Pituitary (anterior and posterior)

- Thyroid & Parathyroid

- Pancreas

- Gonads- Adrenals

3. Muscles (Ch. 47)

- Muscle cell types

- Structure of muscles

- Contraction/relaxation

4. Skeleton (Ch. 47)

- Skeleton types

- Cell types and building bone

Joints and attachments

11 - Endocrine & Musculoskeletal

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