homeostasis

Homeostasis

Feedback Systems - how the body monitors and responds to change in its internal environment to maintain homeostasis. (Balance) (sensors, hypothalamus, effectors)

Positive- amplifies or increases the original change, until a goal is reached. Childbirth (Oxytocin), blood clotting, lactation

Negative - most common, reverses a change to bring things back to normal. Body temp, blood sugar, blood pressure.

Thermoregulation

Process by which the body maintains a stable internal temperature. Key part of homeostasis, if not in normal range enzymes won't work properly. Controlled by

hypothalamus, too hot = sweating (Evaporates), vasodilation (blood vessels widen),

move blood away from centre. Too cold= shivering (muscles contract=heat), vasoconstriction(blood vessels narrow), moves blood into centre of body.

Central and Peripheral Nervous system

CNS is your brain and spinal cord, control centre

PNS all nerves outside brain, spinal cord, (sensory=afferent, motor=efferent). Carries messages to and from CNS.

Sensory-brings signals to CNS from stimulus, motor-sends commands from CNS to body.

Somatic- voluntary motions, skeletal muscles

Autonomic- involuntary, smooth muscles, cardiac muscles

Autonomic split into sympathetic (Fight or flight) and Parasympathetic (rest and digest)

Reflex ars

Automatic response that doesn't use the brain, only spinal cord

Sensory receptor-sensory neuron (PNS) to the interneuron in the CNS to the motor neuron-effecter gland.

Types of hormones

-chemical regulators made by cells that affect cells in another part of the body(growth, metabolism, reproduction, mood) -produced in glands

Steriod- fat soluble(non-polar)(hydrophobic) can travel through membrane (Cholesterol)

Protein- use second messenger system called CAMP, hydrophilic (polar because water soluble)

Endocrine System

Pituitary gland- master gland

Posterior- back, stores and releases, hormones made by hypothalamus. Oxytocin (contractions) uterine muscles, ADH (water balance) kidneys

Anterior- front, makes own hormones but hypothalamus controls the release. TSH (stimulates thyroid gland), ACTH, adrenal cortex, FSH/LH, (reproduction), GH, body, Prolactin, mammary glands, Endorphins, pain receptors in brain.

Pancreas (blood sugar)

Insulin- lowers blood sugar by helping absorb sugar

Glucagon- raises blood glucose by telling liver to release sugar

Thyroid Gland (Metabolism)

Thyroxine(t4) and Triiodothyronine (t3) - increases metabolism and oxygen use

Calcitonin- Lowers blood calcium by storing in bones

Parathyroid glands (calcium balance)

Parathyroid hormone (PTH) - raises blood calcium levels by releasing it from bones.

Adrenal Glands (Stress and survival)

Adrenal cortex(outer), cortisol(long-term stress, raises glucose), Aldosterone(regulates sodium and water balance) and adrenal medulla, Epinephrine and Norepinephrine( fight or flight)

NEURON

NEURON

Starts by an action potential arriving at terminal, then voltage gated Ca2+ open (Ca2+ channel), Ca2+ enters the pre-synaptic neuron) through active transport. Calcium triggers the neurotransmitter vesicle to bind with receptors and release neurotransmitters (Exocytosis), the NT travels across the synaptic cleft and binds with receptors on post-synaptic neuron. (-70mv). Na+ gates will open to cause a action potential if threshold (-55mv) is met. When these gates open its called Depolarization (30mv). Depolarization, sodium gates close and K+ gates open. This causes an undershoot called hyperpolariaztion (-85). Then Na+/K+ pump works to achieve resting (-70mv) again called the factory period

Summation, combination of action potential from 2 neurons

Spatial- jumps from many neurons

Temporal- time dependant

Agonist- mimics NT, increases the affect

Antagonist-blocks response, decreases affect

Excretory System- parts

Produces urine and contributes to homeostasis by excretion of waste(ammonia, salts, urine), maintenance of water-salt balance(blood pressure), acid-base balance/control of

OH)

Inferior vena cava- 02 poor blood back to heart

Kidney- filter waste from blood(make urine)

Renal vein - Clean blood'

Renal Artery- afferent

Urinary System

Vana Cent

Arenal

Aorta- dirty blood to kidney

Ureter- urine from kidney to bladder

Bladder- stores urine

Urethra- urine out body

Kidney

Renal artery (dirty)

Renal pelvis (center)

Renal Medulla

Renal cortex

Ureter

Renal vein (clean)

Afferent arteriole- efferent arteriole-Bowman's capsule- glomerulus- proximal tube

Glomerular capsule- proximal tubule (reabsorption)-descending LOH (reabsorption of

H2O, passive), ascending LOH (reabsorption of NaCl, active), distal tubule(secretion,

medication), collecting duct (reabsorption of H2O/NaCI), peritubular capillaries, Venue, carnes blood to renal vein.

Urine formation

1. Filtration

Solutes + H20 move from dirty blood into glomerulus when a high pressure system filters solutes into Bowmans Capsule

(Proteins, blood cells, glucose are too big to pass into Bowmans capsule)

2. Reabsorption- nephron to blood

600ml of fluid flows through kidney/minute, 120ml is filtered into nephron, 1ml become urine, 119ml gets reabsorbed(BP)

Reabsorption of H2O and solutes is controlled by hormones ADH

3. Secretion- blood to nephron

Movements of waste from blood to nephron via active transport @ distal tubule (medications start to act)

4.Excretion

Removal of remaining wastes from kidney to bladder as urine.