Regents Biology Nervous System

Regents Biology Why do animals need a nervous system? What characteristics do animals need in a nervous system?  fast  accurate  reset quickly Remember… think about the bunny… Poor bunny!

Regents Biology Nervous System Central nervous system  brain & spinal chord Peripheral nervous system  nerves from senses  nerves to muscles cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve

Regents Biology Nervous system cells dendrites cell body axon synapse  Neuron  a nerve cell signal direction signal direction

Regents Biology Synapse Junction between nerve cells  1st cell releases chemical to trigger next cell  this is where drugs affect nervous system

Regents Biology Neurotransmitter  Chemical messenger that transmits a signal from a nerve cell to a receptor  Receptor – another nerve cell a muscle an organ

Regents Biology Types of neurons sensory neuron (from senses) interneuron (brain & spinal chord) motor neuron (to muscle)

Regents Biology Human brain

Regents Biology Cerebrum specialization Regions of the cerebrum are specialized for different functions Lobes  frontal  temporal  occipital  parietal

Regents Biology Simplest Nerve Circuit  Reflex, or automatic response  rapid response  automated  signal only goes to spinal cord  no higher level processing  advantage  essential actions  don’t need to think or make decisions about  blinking  balance  pupil dilation  startle

Regents Biology Endocrine System Hormones & Homeostasis

Regents Biology Homeostasis  maintaining internal balance in the body organism must keep internal conditions stable even if environment changes also called “dynamic equilibrium”  example: body temperature humans:  too cold = shiver  too warm = sweat

Regents Biology Regulation How we maintain homeostasis  nervous system nerve signals control body functions  endocrine system hormones chemical signals control body functions

Regents Biology Controlling Body Temperature high low nerve signals sweat nerve signals brain body temperature shiver brain dilates surface blood vessels constricts surface blood vessels Nervous System Control Feedback

Regents Biology Hormones Why are hormones needed?  chemical messages from one body part to cells in other parts of body  communication needed to coordinate whole body  maintaining homeostasis growth hormones

Regents Biology Endocrine System Endocrine system releases hormones  glands which secrete (release) chemical signals into blood chemicals cause changes in other parts of body  growth hormones  sex hormones  response hormones  metabolism hormones  and more….

Regents Biology Responding to hormones Lock and key system  hormone fits receptor on “target” cell target cell non- target cells secreting cell can’t read signal

Regents Biology Glands Pineal  melatonin Pituitary  many hormones: master gland Thyroid  thyroxine Adrenal  adrenaline Pancreas  insulin, glucagon Ovary  estrogen Testes  testosterone

Regents Biology Maintaining homeostasis high low hormone 1 lowers body condition hormone 2 gland specific body condition raises body condition gland Feedback

Regents Biology Negative Feedback Response to changed body condition  if body is high or low from normal level signal tells body to make changes that will bring body back to normal level  once body is back to normal level, signal is turned off high hormone 1 lowers body condition gland specific body condition

Regents Biology liver pancreas liver Regulation of Blood Sugar blood sugar level (90mg/100ml) insulin body cells take up sugar from blood liver stores sugar reduces appetite glucagon pancreas liver releases sugar triggers hunger high low Feedback Endocrine System Control

Regents Biology Endocrine System Hormones & Reproduction

Regents Biology Sex & Growth Hormones Large scale body changes  how do they work turn genes on start new processes in the body by turning genes on that were lying “dormant”

Regents Biology Reproductive hormones Testosterone  from testes  sperm production & secondary sexual characteristics Estrogen  from ovaries  egg production, preparing uterus for fertilized egg & secondary sexual characteristics

Regents Biology Sperm production  over 100 million produced per day!  ~2.5 million released per drop! Male reproductive system

Regents Biology spermatocytes seminiferous tubule sperm

Regents Biology Male reproductive system Testes & epididymis  sperm production & maturation Glands  seminal vesicles, prostate, bulbourethal  produce seminal fluid nutrient-rich

Regents Biology Female reproductive system

Regents Biology DO NOW How does the endocrine system maintain homeostasis in the body?

Regents Biology Female reproductive system

Regents Biology LH FSH estrogen progesterone lining of uterus egg development ovulation = egg release corpus luteum days Menstrual cycle Controlled by interaction of 4 hormones  FSH & LH  estrogen  progesterone

Regents Biology Fertilization

Regents Biology gQW6FG4

Regents Biology Placenta Food & gases diffuse across blood vessels

Regents Biology Respiratory System

Regents Biology Why do we need a respiratory system? Need O 2 in  for cellular respiration  make ATP Need CO 2 out  waste product O2O2 food ATP CO 2

Regents Biology Lungs alveoli  trachea  bronchi  bronchioles  alveoli capillaries (circulatory system)

Regents Biology Lungs Structure spongy texture high surface area more absorption of O 2  alveoli small air sacs  moist lining mucus traps dust, pollen, particles  covered by cilia hair-like extensions of cells move mucus upward to clear out lungs

Regents Biology Moving gases into bloodstream Inhale  O 2 passes from alveoli to blood  by diffusion Exhale  CO 2 passes from blood to alveoli  by diffusion capillaries (circulatory system)

Regents Biology Excretory System Kidneys

Regents Biology Animal cells move material across the cell membrane by diffusion  nutrients in from digestive system  fuels for energy in from digestive system  oxygen in from respiratory system  waste out CO 2, urea from cells to respiratory system, to excretory system What do animal cells do to stay alive? O2O2 sugar nutrients CO 2 urea nutrients O2O2

Regents Biology Keeping an animal alive Had to evolve organ systems for:  getting materials in & around digestive system respiratory system circulatory system  removing wastes respiratory system excretory system

Regents Biology What liquid waste do we make? Digesting protein makes poison  nitrogen waste = ammonia = poison H CO 2 + H 2 O NH 2 = ammonia H H N C—OH || O H | —C— |

Regents Biology Human kidney Mammals have a pair of bean-shaped kidneys  supplied with blood by a renal artery and a renal vein

Regents Biology Bladder