Homeostasis and Endocrine Signaling. Tissues Figure 32.2 4 major types: Epithelial – found on outside of the body and lining organs and cavities. Muscle.

Homeostasis and Endocrine Signaling

Tissues• Figure 32.2

• 4 major types:• Epithelial – found on outside of the body and lining organs and

cavities.

• Muscle – 3 types• Cardiac – heart tissue, involuntary• Smooth – involuntary actions in body, organs, blood vessels• Skeletal – muscle that moves, attaches to bone, voluntary

• Nervous tissue – the neuron, sends impulses, communication• Glia cells are nerve helping cells to the neurons

• Connective tissue – diverse group of tissues scattered throughout body and extracellular matrix• Bone – calcified hard matrix• Blood – liquid matrix• Cartilage – ear, nose, gel like matrix• Dense fibrous – tendons and ligaments• Adipose - fat• Areolar – loose fibrous connecting tissue

Regulator or Conformer?• Animals that are regulators uses internal mechanisms to

control internal change – endothermic, homeothermic, warm blooded

• Animals that are conformers – internal condition changes in accordance with external changes, ectothermic, cold blooded

• Homeostasis – maintenance of a constant internal balance• examples,- body temp, blood glucose levels…• Negative feedback – when body is out of homeostasis and it is

brought back.• Positive feedback – when body is brought out of homeostasis

purposely for a short period of time, childbirth and oxytocin

Thermoregulation (heat)• Figure 32.3

Figure 32.4

Sensor/control center:Thermostatturns heater off.

Sensor/control center:Thermostatturns heater on.

Stimulus:Room

temperatureincreases.

Stimulus:Room

temperaturedecreases.

Roomtemperatureincreases.

Roomtemperaturedecreases.

Set point:Room temperature

at 20C

Response:Heating stops.

Response:Heating starts.

Endocrine system• Endocrine system – communication via hormones that are

released by endocrine glands into the blood stream.• Hormones – chemical messengers• Exocrine glands – figure 32.11

• Exocrine glands – integumentary system, release product to cavity or outside the body, sweat.

• Nervous system – rapid communication using neurons and nerve impulses

• All run by Stimulus/Response mechanism

Figure 32.11a

PancreasInsulinGlucagon

Testes(in males)Androgens

Parathyroid glandsParathyroid hormone (PTH)

Ovaries (in females)EstrogensProgestins

Thyroid glandThyroid hormone(T3 and T4)Calcitonin

Pineal glandMelatonin

Major Endocrine Glandsand Their Hormones

Hypothalamus

Pituitary gland Anterior pituitary

Posterior pituitaryOxytocinVasopressin(antidiuretichormone, ADH)

Adrenal glands(atop kidneys)

Adrenal medullaEpinephrine and norepinephrine Adrenal cortexGlucocorticoids Mineralocorticoids

Figure 32.8Sensor/controlcenter: Thermostatin hypothalamus

Stimulus:Decreased body

temperature

Bodytemperatureincreases.

Bodytemperaturedecreases.

Homeostasis:Internal body

temperature ofapproximately

36–38C

Response:Blood vesselsin skin dilate.

Response: Shivering

Sensor/controlcenter: Thermostatin hypothalamus

Response:Blood vesselsin skin constrict.

Stimulus:Increased body

temperature

Response: Sweat

Figure 32.9

Cellbody ofneuron

Response

Hormone

Nerveimpulse

Signaltravelseverywhere.

Signaltravels toa specificlocation.

Response

Stimulus Stimulus

Nerveimpulse

Blood vessel

Endocrinecell

(a) Signaling by hormones

Axons

Axon

(b) Signaling by neurons

Osmoregulation (fluids)• How animals control solute concentrations in the interstitial

fluid and balance water gain and loss

• Excretory system – releasing of nitrogenous and metabolic waste products (kidney)

• Osmoconformer – being isoosmotic with its surroundings, marine animals

• Osmoregulator – to control internal osmolarity independent of the environment. Allows animals to live in freshwater/terrestrial habitats.

Nitrogenous wastes in animals• 32.16

Figure 32.16

Most aquaticanimals, includingmost bony fishes

Proteins Nucleic acids

Aminoacids

Nitrogenousbases

Amino groups

Mammals, mostamphibians, sharks,

some bony fishes

Many reptiles(including birds),

insects, land snails

Ammonia Urea Uric acid

Figure 32.16a

Most aquaticanimals, includingmost bony fishes

Mammals, mostamphibians, sharks,

some bony fishes

Many reptiles(including birds),

insects, land snails

Ammonia Urea Uric acid

The excretory process• Urine formation: 32.17

Figure 32.17

CapillaryFiltration

Excretorytubule

Filtrate

Reabsorption

SecretionU

rine

Excretion

The Kidney – figure 32.19

Figure 32.19b

Kidney Structure

Renal cortex

Nephron Organization

Nephron Types

Renal medulla

Renal artery

Renal vein

Renal pelvis

Ureter

Renal cortex

Renal medulla

Cortical nephron

Juxtamedullary nephron

Collectingduct

Branch ofrenal vein

Vasarecta

Efferentarteriole

fromglomerulus

Distaltubule

Afferent arteriolefrom renal artery

Glomerulus

Bowman’scapsule

Proximaltubule

Peritubularcapillaries

Descendinglimb

Ascendinglimb

Loop of

Henle

Figure 32.19bcNephron Organization

Collectingduct

Branch ofrenal vein

Vasarecta

Efferentarteriole

fromglomerulus

Distaltubule

Afferent arteriolefrom renal artery

GlomerulusBowman’scapsule

Proximaltubule

Peritubularcapillaries

Descendinglimb

Ascendinglimb

Loop of

Henle

Figure 32.20

Filtrate

OUTERMEDULLA

H2OSalts (NaCI and others)

HCO3−

Glucose, amino acids

H

Some drugs

Passive transportActive transport

Key

INNERMEDULLA

CORTEX

Descending limbof loop of Henle

H2O

Interstitialfluid

NH3H

NutrientsHCO3

− K

NaCI

Proximal tubule

H2O

Thick segmentof ascending limb

H

Urea

HCO3−

K

NaCI

Distal tubule

H2O

Thin segmentof ascending limb

NaCI

H2ONaCI

NaCI

Collectingduct

1

23

5

4

3Urea

Adaptations • Based on where you live, there are adaptations to the kidney

• Hyperosmotic urine (dessert animals) – long loops of Henle that extend deep into the medulla

• Birds – shorter loop of Henle, les concentrated urine compared to mammals – uric acid is product to help conserve water.

Homeostatic regulation of kidney

• 32.23 antidiruretic hormone

Figure 32.23-3

Distaltubule

H2Oreabsorption

STIMULUS:Increasein blood

osmolarity

Drinkingof fluids

Increasedpermeability

Osmoreceptorstrigger release

of ADH.Thirst

ADH

Collecting duct

Homeostasis