Bio 30 Unit A: Nervous and Endocrine Systems

Optimal Body Temperature

Optimal Body Temperature

37 degrees celsius

Optimal blood glucose levels

0.1%

Optimal blood pH

7.35

Homeostasis

Balance

Dynamic Equilibrium

Body trying to adapt to outside conditions

Negative Feedback Loop

Products eventually stop it.

Is a series of actions occurring in an attempt to maintain equilibrium.

Control Systems

Work within feedback loops to maintain equilibrium

Has a receptor, coordinating center, and effector.

Receptor

Monitors the values compared to normal

(Thermometer.)

(Detects increased CO2)

Coordinating Center

Determines the optimal conditions of the body and reacts to the change caused by stimulus

(Thermostat)

(Brain/nerve cells)

Effector

Responds to signals sent by the control center.

(Furnace)

(Muscles increase breathing, Decreases CO2)

Positive Feedback Loop

Reinforces change not restricting it.

Accomplishes physiological events rapidly then stops rapidly (although it tries to continue)

Hormones

Speed up or slow down cell functions

Produced by glands move to blood then the target.

two types.

Non-target hormones

Affect many cells

ex. insulin, hGH (human growth hormone), epinephrine (adrenaline)

Target Hormones

Affect a specific cell or tissue.

ex. Gastrin

Water-soluble

Amino Acid derivatives

Can’t cross membrane (Membrane lipid based)

Bind to membrane receptor (On the outside of the membrane)

Fat-soluble

Steroids

Can cross the membrane (Membrane lipid based)

Diffuse and binds to cytoplasmic receptors (On the inside of the membrane).

The Pituitary

Controls other endocrine glands

Connected to hypothalamus

Produces and stores hormones; stimulated by hypothalamus via nerves and hormones.

Has Posterior and Anterior lobes

Posterior Lobe

Receives hormones

Releases ADH (antidiuretic hormone from hypothalamus. Regulates water)

Anterior Lobe

Synthesizes hormones; controlled by hypothalamus.

Releasing factors stimulates secretion; inhibiting factors stop pituitary secretions.

DNA to produce hormones

Genetic engineer transfers human genes to bacteria for hormone production.

hGH promotes bone and muscle growth; lack can cause dwarfism and fatigue

Body reaction to food

Glucose leads to a rise in blood sugar.

Body reaction to fasting

Starvation makes blood sugar lower.

Pancreas beta cells

Releases insulin for sugar to enter cells

Glucose Storage

Live takes excess glucose into glycogen

Pancreas Alpha Cells

Releases glucagon - glycogen —> glucose

Works to raise blood sugar.

Affects of Insufficient Insulin

Nerve damage (caused by inflammation choking nerve cells)

Blindness, renal failure, amputation.

Hyperglycemia

Increased blood sugar after meals

Is an byproduct insufficient insulin

What hyperglycemia does

Increased concentration of filtrate in nephron which increases urine.

Glucose does not reach cells which causes fatigue

Body uses fats and proteins as a fuel source instead which causes acetone breath.

Type One Diabetes

Degeneration of pancreatic beta cells

Is from childhood.

Is rare (only 10% chance)

Type Two Diabetes

Body becomes resistant to insulin

Treated with diet, exercise, and medication

Common (90%)

Gestational Diabetes

Affects 2-4% of pregnancies and increases risk of type two diabetes in both the mother and child.

Edmonton Protocol

A transplant used to treat type one diabetes.

Because the body usually rejects this transplant immunosuppressant drugs are used help although it weakens patient.

It is when you place pancreatic tissues on the liver which helps in grow into the graft.

Adrenal Glands

Located on top of the kidneys

Two primary parts: Medulla and cortex.

Adrenal Medulla

Associated with sympathetic nervous system.

Core of adrenal gland

Regulated by hypothalamus

Makes epinephrine (adrenaline) and norepinephrine.

Adrenal Cortex

Regulated by endocrine system

Outer part of adrenal gland.

Makes mineralcorticoids, aldosterone, sex hormones (DHEA —> testosterone and estrogen), glucocorticoids - cortisol.

HPA axis short term

Not negative feedback loop

Hypothalamus uses sympathetic nervous system to send a signal to the adrenal gland (medulla) to make Epinephrine and norepinephrine.

HPA Axis Long Term

Negative Feedback Loop.

Hypothalamus makes CRH which goes to the anterior pituitary to release adrenocorticotropic hormone (ACTH) which stimulates the adrenal gland (cortex) making cortisol. Then the hypothalamus and the Ant. Pit detect the cortisol and stop producing their hormones.

Hormones that affect blood sugar

Insulin

Glucagon

Epinephrine

Norepinephrine

Cortisol

Human Growth Hormone

Insulin

Made in Pancreas

Increases glucose uptake.

Allows conversion of glucose to glycogen

Brings a decrease in blood sugar.

Glucagon

Made in pancreas

Promotes conversion of glycogen to glucose

Brings an increase in blood sugar

Epinephrine and Norepinephrine

Made in adrenal medulla

Promotes conversion of glycogen to glucose

Increases blood sugar.

Increases heart rate, breathing, and cell metabolism

Cortisol

Made in adrenal cortex

Typer of glucocorticoid

Promotes conversion of amino acids to glucose

Promotes breakdown of fats to fatty acids.

Decreases glucose uptake by muscles

Brings increased blood sugar in response to stress.

Human Growth Hormone (hGH)

Made in Anterior Pituitary

Adjusts blood sugar during fasting to find fuel.

Promotes elongation of skeleton

Promotes protein synthesis by increasing uptake of amino acids by cells.

Causes a switch in cellular fuels from glucose to fatty acids.

The Three Glands

Thyroid

Parathyroid

Anterior Pituitary

Thyroid Gland

Responsible for metabolism

Is in the throat.

Fast Metabolism

Thyroid Gland

HPT axis

No weight gain, you feel warm

Slow Metabolism

Thyroid Gland

Lower production

More storage as glycogen and fat, muscle weakness, cold, dry skin/hair.

Thyroxine (T4) and Triiodothyronine (T3)

Made in Thyroid

Regulate metabolism (cell resp) and cell differentiation.

Increases cell specialization in embryos and adults.

Regulates rate at which glucose is oxidized within body cells

Calcitonin

Made in thyroid

Regulates Ca+ levels in blood and bones.

Calcium storage

Lowers calcium levels in blood

HPT Axis

Uses T3 and T4 to activate hypothalamus and anterior pituitary, which then goes to thyroid to increase the chemicals.

Deals with chemical concentration, cellular respiration, and temperature.

Iodine

Without it there is no T3 and T4 so the thyroid grows a goiter.

Goiter

Swelling of the thyroid gland.

Tight throat, coughing, difficulty breathing or swallowing, etc.

Parathyroid Gland

Regulates Ca2+ balance in the body.

Removal causes muscular and nervous dysfunction.

Parathyroid Hormone (PTH)

Made in parathyroid glands

Activates Vitamin D to promote bone group

Inhibits calcitonin from thyroid (Increased Ca absorption in kidneys and intestine to go to the blood.) (Ca and phosphate is released from the bone)

Raises calcium levels in blood.

Hyposecretion of hGH

Can cause dwarfism in children

Prevents body from properly growing.

Hypersecretion of hGH

Gigantism in children and acromegaly in adults

Causes rapid and dramatic growth

Antidiuretic Hormone (ADH)

Conserves water

Osmoreceptors

In hypothalamus

Release water through osmosis when there is an increase in blood solute concentration, causing them to shrink.

The shrunken versions trigger release of ADH and activate a thirst response

Diabetes Insipidus

Bland (little glucose in urine)

Common

Posterior pituitary does not produce ADH or nephrons are resistant to ADH

Not life threatening.

RAAS system

Renin

Angiotensin

Aldosterone

Juxtaglomerular Apparatus

Has blood pressure receptors that release renin

Renin

Converts angiotensinogen (from liver) to angiotensin which:

1. Constricts blood vessels to increase blood pressure

2. Release aldosterone from adrenal cortex

Aldosterone

Increases sodium reabsorption in nephrons (into blood)

Osmotic pressure moves water into blood.

Makes sodium and water rush into blood

High blood sugar problems

Increased osmotic pressure (water rushes into blood)

Increase blood pressure

High heart rate problems

Increased blood pressure

Damage heart muscle

High blood pressure problems

Vessel ruptures

blood clotting

aneurysm

Chronic Stress can cause…

Heart disease, autoimmune disease and mental disorders.

Prostaglandins

Hormones made and used by the same cell (They don’t travel)

During stress they trigger inflammation:

Increase blood flow, clotting pathway in blood vessels, contribute to fever and pain.

Blocked by aspirin

Anabolic steroids

Mimic testosterone

Trigger muscle building

Makes circulatory system work harder (bad)

Fuses growth plates

Causes anger

Central Nervous System

The Brain and spine.

Coordinating center

Peripheral Nervous System

Other nerves.

Relays info between body and CNS

Nerves have neurilemma

Autonomic Nervous System

Part of PNS

Communicates with organs and glands (internal involuntary functions).

CNS —> preganglionic neuron —> ganglion —> postganglionic neuron —> organ/muscle/gland

Sympathetic (stress)

Parasympathetic (peace)

Connects CNS to inside.

Somatic Nervous System

Part of PNS

Communicates with senses and voluntary movement.

Sensory NS; afferent, sensory input

Motor NS; efferent, motor output.

Connects CNS to the outside.

Governed by 12 cranial nerves and 31 spinal nerves

Glial cells

Structural and metabolic support to neurons.

Dendrites

Listens and receives messages.

Myelin Sheath

Schwann cells, myelin, nodes of Ranvier work together to speed through messages.

Axon

Sends messages

Myelinated, have nodes of Ranvier and increased diameter.

3 Types of Nerve Cells

Sensory (Afferent)

Interneurons

Motor (Efferent)

Sensory Nerve Cell

Relay info from sensory receptors.

Groups = ganglia

Afferent

Interneurons Nerve Cells

Links neurons

In spine.

Motor

Relay info to effectors: muscles, glands, etc.

Efferent

Neurilemma

Allows for slow repair in the peripheral nervous system (grey).

Reflex Arc

Sensory Receptor - receives stimulation

Sensory Neuron (ganglion in groups) - sends electrical impulses

Interneuron (in spine) - making the decisions

Motor Neuron - carries efferent impulses to the effector

Effector - perform reflex action

Plasticity

The brains ability to grow, learn.

Axons grow and myleinate.

Impulse traveling

Going along the axon by switching between resting potential and action potential.

Sodium-Potassium Pump

The pump that moves sodium and potassium across the cell membrane.

Movement of Action Potential

Does not move but triggers farther action potential (domino effect)

Depolarization causes sodium channels to open nearby.

Backwards impulses impossible b/c of refractory period.

Signal jumps between nodes of Ranvier.

Threshold

Nerves only fire when ________ is met.

Overshooting _________ does not affect effector.

Rest (Action Potential Sequence)

1st

Everything in system closed

-70mV

Straight line on graph.

Threshold (Action Potential Sequence)

2nd

Some Na+ starts going through Na+ pump.

-55mV

Lower part of climbing sequence on graph.

Depolarization (Action Potential Sequence)

3rd

Na+ rushes through Na+ pump.

Anything above -55mV around 0mV

The incline on the graph.

Channel Changer (Action Potential Sequence)

4th

Na+ closes and K+ pump opens with K+ starting to go through.

40mV

The maximum point of the graph.

Repolarization (Action Potential Sequence)

5th

All K+ moves through K+ pump.

Around 0mV

The declining section of the graph.

Hyperpolarization (Action Potential Sequence)

6th

Too much K+ passes through the K+ pump

-75mV

Point of graph past the baseline

Refractory Period (Action Potential Sequence)

7th

Molecules travel through sodium-potassium pump to restore everything to normal.

-70mV

Final part of graph that matches the first part at the baseline.

Synapses

tiny gaps between neurons (20 nanometers) most involve many neurons.

Presynaptic neuron

Releases neurotransmitter in vesicles

Neurotransmitters

Excitatory and Inhibitory

Excitatory

Increases polarization by opening Na+ gates

Inhibitory

Decreases depolarization by opening K+ gates