Lesson 1 Homeostasis Lesson Objectives To know how

Lesson 1: Homeostasis

Lesson Objectives To know how to keep conditions inside your body constant. To know how to get rid of waste products. To know how the body monitor temperature.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Starter Q 1: What happens when you do exercise? Q 2: Why?

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Running You begin to sweat. You begin to breathe more heavily.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Control Your body is trying to maintain a constant internal environment. This is called Homeostasis. Why?

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Question What is the equation for respiration? Glucose + Oxygen Carbon Dioxide + Water

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Homeostasis Conditions inside your body need to be kept steady so that cells can function properly. Therefore, a balance between what goes in and what comes out needs to be maintained.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Homeostasis – Example 1 Levels of Carbon Dioxide. • Respiration in cells produced carbon dioxide constantly, which needs to be removed. Too much can lower the p. H and make it too acidic. • Lower p. H would therefore affect enzymes. • It is removed in the air we breathe out.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Homeostasis – Example 2 Urea. • Produced by the liver. • Made of excess amino acids, from eating too much protein. • It is poisonous if it build up. • Filtered by kidneys. • Removed in urine along with water and salt. • Stored in bladder.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Homeostasis – Example 3 Water and Ions: • Water is lost through breathing, sweating and urine. • Ions are lost in sweat and urine. (sweat tastes salty due to sodium ions)

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, How? The body regulates the environment through a process called ‘negative feedback’. 1. The body detects a change in the environment. 2. This triggers a response that counteracts the change (e. g. rise in body temperature causes a response which lowers the body temperature). 3. Therefore, the internal environment stays at the norm (the level that cells work best) This only works within certain limits – if the change is too great then it may not be possible to counteract – hyperthermia, heatstroke.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Negative Feedback Increase from normal level detected Response counteracts the increase Body Temperature Normal Level Decrease from normal level detected Response counteracts the decrease Time

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Body temperature Q: What is normal body temperature? A: 37 C Q: What chemicals help to aid digestion? A: Enzymes Q: At what temperature, do enzymes work best? A: 37 C

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Body temperature This can rise due to: • Exercise • Fevers due to disease • External temperature changes.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Body temperature 37 C is body temperature and it needs to be kept constant. If it rises too much enzymes will become denatured and no longer work, cell may die, etc. The brain has its own personal thermostat – contains receptors sensitive to blood temperature – thermoregulatory centre. It also receives feedback from the skin – can detect changes as small at 0. 5 C.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, Your skin

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, 1. When you get too COLD! Hairs (B) stand up on end (to trap air which provides an insulating layer) 2. Very little sweat is produced 3. Blood vessels near surface constrict (C) (so less heat can be transferred from the blood to the surroundings). 4. You shiver (movement generates heat in the muscles) 5. You can put on more clothes.

Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, When you get too HOT! 1. Hairs lie flat 2. Lots of sweat (E) is produced (when sweat evaporates it transfers heat from you to the environment) 3. Blood vessels close to the surface (F) of the skin dilate (open) to allow more blood to the surface. (transfers heat from the blood to the surroundings) 4. You may take off clothes to help cool down.

Review Objectives Keywords: Homeostasis, Liver, Urea, Kidney, Thermoregulatory centre, I still feel unsure. I need some more help to understand. I feel ok. I need to do some more work to check my understanding. I am happy and feel I understand can explain the main points.

Book Pages • Honors Pages (Cornell Notes and Vocabulary Pages) – Homeostasis, Kidneys, Liver: Pg 895 -896, 1000 -1001, 985 -989, Pg 982 – Respiratory System: Pg 956 -963 • Honors Pages (Bookwork) – HKL: Pg 896#2, Pg 917# 2, 12, Pg 989 # 1, 2, 5 and Pg 993 # 7, 10, 23 -25 – Resp Sys: Pg 963 # 1 -4, Pg 967#8 -10, 23 -25

Book Pages • College Prep Pages (Cornell Notes and Vocabulary Pages) – Homeostasis, Kidneys, Liver: • Tiger Book (Class): Pg 918 – 919, 920 -924 • Eyeball Book (Home): Pg 593, 596, 698 -700, 640, 707 -708, 701 -705 – Respiratory System: • Tiger Book (Class): Pgs 895 – 900 • Eyeball Book (Home): Pg 667 -671 • College Prep Pages (Bookwork) – HKL: • Tiger Book (Class): Pg 924 #s 1 -5, Pg 919 # 4, Pg 926 # 10 - 12 • Eyeball Book (Home): Pg 705 # 1 -2, Pg 708 #1 -3, Pg 700#2, Pg 650 #5, Pg 596 # 1, 3, 4 Pg 606 #2, 20 – Respiratory: • Tiger Book (Class): Pgs 900 #s 1 -3, 5, Pg 902 #s 10 -12 • Eyeball Book (Home): Pg 671 # 1 -3, Pg 669 #1 -3, Pg 672 # 6, 7, 14