t3

• Skin regulating temperature


  1. In cold conditions - Vasoconstriction, erector muscles for body hair contracts, shivering, increased rate of metabolism

  2. In hot conditions - Vasodilation, sweat glands producing sweat, decreased rate of metabolism
• Kidney filtering blood


  Through the glomerulus via ultrafiltration in the Bowman's capsule/glomerular capsule of the nephron, forcing small molecules out into the proximal convoluted tubule

  
• Proximal convoluted tubule and loop of Henle

  Responsible for selective reabsorption of vital substances (e.g, water and glucose) back into the blood
• Proximal convoluted tubule


  Responsible for reabsorption of water, amino acids, and glucose
• Loop of Henle


  Responsible for reabsorption of salts
• Distal convoluted tubule


  Responsible for reabsorption of electrolytes and pH regulation
• Collecting duct


  Responsible for reabsorption of water
• ADH


  A hormone produced by the hypothalamus that regulates water retention in the body by making the collecting ducts more permeable/impermeable to water
• Water present in the body


  The more water, the less ADH will be released, making the body urinate more. The less water, the more ADH will be released, making the body urinate less.
• Osmoregulation


  Homeostasis of water and salt levels in the body
• Nervous system


  • Consists of the central nervous system (CNS) and the peripheral nervous system (PNS)
  • Uses electrical impulses to transmit signals rapidly between cells and the hormonal system
• Hormonal system


  • Releases hormones into the bloodstream to carry messages to target cells
• Examples of hormones


  • Adrenaline
  • Estrogen
  • Testosterone
  • ADH
  • Progesterone
  • LH
  • Insulin
  • FSH
• Hormonal system vs Nervous system


  Hormonal system uses hormones for communication, whilst the nervous system uses electrical impulses for signals
• Central Nervous System (CNS)


  • Made up of the brain and spinal cord
  • Linked to sense organs by nerves
• Peripheral Nervous System (PNS)


  • Nerve systems that lie outside the brain and spinal cord
• Coordinated response


  Stimulus -> receptor -> CNS -> effector -> response
• Reflex


  Processed in the spinal cord
• Coordinated response


  Processed in the CNS
• Endocrine system


  Releases hormones into the bloodstream to carry messages to target cells
• Hormones


  • adrenaline > released via adrenal glands, estrogen > ovaries and body fat, testosterone > in gonads (testes and ovaries), ADH > hypothalamus, progesterone > adrenal cortex + gonads, LH > pituitary gland, insulin > pancreas, FSH > pituitary gland
• Hormones


  • ADH helps water regulation, adrenaline initiates fight or flight response, estrogen progesterone and FSH are responsible for growth in women, testosterone for growth in men, LH for growth in both sexes
• Difference between hormonal and nervous system


  Hormonal system uses hormones for communication, nervous system uses electrical impulses for signals
• Central Nervous System (CNS)


  Made up of the brain and spinal cord, Linked to sense organs by nerves
• Peripheral Nervous System (PNS)


  Nerve systems that lie outside the brain and spinal cord
• Reflex vs coordinated response


  Reflexes are processed in the spinal cord, responses are processed in the brain. Reflexes are often primal instincts, responses are just responses to a stimuli

  
• Types of neurons


  • Sensory, relay, motor
• Sensory neurons


  Sense changes in surroundings and transports these perceptions to the CNS
• Relay neurons


  Allow communication between the sensory and motor neurons
• Motor neurons


  Relay responses to the effectors
• Synapses


  Gaps between neurons in which electrical signals are converted into chemical signals (neurotransmitters) to be transferred to the next neuron
• Receptors


  Things that perceive changes in the environment (e.g. the eye, ears, skin)
• Eye


  Acts as a receptor of light to transmit signals to the brain, utilises its flexible lens to focus on things at different distances
• Focusing on long-distance objects


  Circular muscles contract, radial muscles relax, elongating the lens, which allows less light to pass through, causing the pupil to constrict
• Focusing on short-distance objects


  Circular muscles relax, radial muscles contract, fattening the lens, which allows more light to pass through, causing the pupil to dilate
• Pupil


  Dilates in dark light to allow more light into the eye, constricts in bright light to prevent eye damage
• Differences between plant and animal cells


  • Plant cells have a cell wall, rigid and geometric structure, chloroplasts, large vacuole. Animal cells only have cell membrane, loose and non-rigid structure, lack chloroplasts, no vacuole
• Plants are autotrophs, meaning they produce food by themselves
• Mineral ions required by plants


  • Magnesium > chlorophyll production, Nitrates & Phosphates > amino acids and growth, Sulphates > enzymes for photosynthesis, Potassium > strong stems, protects from temperature/bugs, regulates stomata and enzymes
• Plants are eukaryotic cells, meaning their cells have membrane-bound DNA structures