Hormonal Co-ordination in Animals - The Endocrine System + Kidneys + Kidney Treatments+ Flashcards
1
Q
What is the endocrine system and what does it do?
A
- made of glands
- secretes hormones into bloodstream
- blood carries hormone to the target organ
- effects are slower, longer lasting compared to nervous system
2
Q
What are hormones and what is their function?
A
- hormones are chemical molecules released directly into the blood
- are carried in the blood to other parts of the body, only effect particular cells in particular organs - target organs
- hormones control things in organs and cells that need constant adjustment
3
Q
where are hormones produced?
A
produced and secreted by various glands, called endocrine glands
4
Q
hormones have short/long lasting effects?
A
long
5
Q
name 6 examples of glands within the human body:
A
- the pituitary gland
- ovaries - females only
- testes - male only
- thyroid
- adrenal gland
- pancreas
6
Q
what is the function of the pituitary gland?
A
- produces many hormones that regulate body conditions
- hormones act on other glands–> directing them to release hormones that bring about change
7
Q
what is the function of the testes?
A
- produces testosterone –> controls puberty + sperm production in males
7
Q
what is the function of the ovaries?
A
- produces **oestrogen –> involved in the menstrual cycle
8
Q
what is the function of the thyroid?
A
- produces thyroxine –> regulates things like :
- rate of metabolism
- heart rate
- body temperature
9
Q
what is the function of the adrenal gland?
A
- produced adrenaline
- used to prepare the body for ‘flight or fight’ response
10
Q
what is the function of the pancreas?
A
- produces insulin –> regulates blood glucose level
11
Q
what are the differences between hormones and nerves?
A
NERVES:
- very fast reaction
- act for a very short time
- act on a very precise area
HORMONES:
- slower action
- acts for a long time
- acts in a more general way
12
Q
what is blood glucose controlled by?
A
- homeostasis
- insulin and glycagon are the 2 hormones involved
13
Q
What is the pancreas role in maintaining the blood glucose levels
A
- pancreas continuously monitors blood glucose levels
- Produces 2 hormones involved into regulation:
- insulin
- glucagon
- secreted into the blood stream
- travel in blood to their target organs (the liver) where response occurs
14
Q
When blood glucose levels are too high what hormone is secreted, the process and what are the effects?
A
- pancreas secretes insulin
- Effect on Liver : insulin makes
liver converts glucose to glycogen, and stored in liver and skeletal muscles - Effect on glucose levels: goes down as glucose is removed from blood
15
Q
When blood glucose levels are too low what hormone is secreted and what are the effects
A
- pancreas secretes glucagon
- glucagon makes liver converts glycogen —> glucose
- glucose levels increase and released into blood from the liver cells
16
Q
The blood glucose level is kept constant by a n………….. f……………… m…………….
A
Negative feedback mechanism
17
Q
What is negative feedback ?
A
- when the internal factor rises above the normal level, the body responds by lowering the factor
- vice versa when the internal factor is below the normal level
18
Q
What is the kidney’s main function
A
To maintain the water balance of the body
- excess water, excess ions and urea are removed via the kidneys in the urine
19
Q
The kidney is a specialised organ in which body system
A
Urinary system
20
Q
How is water taken into the body?
A
ingesting food and drinks
21
Q
What are the 2 ways water can leave the body?
A
- via the lungs during Exhalation
- from the skin as Sweat
22
Q
What substances are lost in sweat
A
- water
- ions
- urea
23
Q
What happens during the filtration process?
A
- kidneys make urine by taking waste products out of your blood.
- substances are filtered out of the blood as it passes through the kidneys
24
What is selective re-absorption?
- useful substances like **glucose, some ions** and the right amount of **water** are absorbed back into the blood after the kidney filtrates unwanted substances out
25
How is Urea excreted from the body:
1. **Excess proteins and amino acids** cant be stored in the body — a process called **deamination** in the **liver** converts some **amino acid** into **fats and carbohydrates**, which can be stored
2. **ammonia** is produced as a **waste product**
3. **ammonia** is **toxic** so its converted to **urea** in the **liver**. Then transported to the **kidneys**, where its **filtered out** of blood and excreted from body in **urine**
26
What are the effects of the ion concentration changing?
1. Ions such as **sodium** enter the body through the ingestion of **food** and are absorbed into the blood
2. If ion concentration **too high** —> **cells loose water** and become **crenated** / if concentration **too low** —> **cells** may **rupture**
27
How is the right amount of ions maintained within the body?
- some ions are lost in **sweat** —> but this amount is **not regulated**
1. right amount is maintained by the **kidneys**
- right amount of ions are **reabsorbed** back into blood **after filtration**
- kidneys **filter excess ions** out of blood and **excreted** from body into **urine**
28
Why is water regulation essential?
To **prevent** cells **rupturing** or **crenating**
29
How does the body constantly balance the intake and output of water?
Uncontrolled Loss
- lost water from **skin** or **sweat**
- lost from **lungs** when **breathing out**
Controlled lost
- the amount we **consume**
- **kidneys remove excess water** from blood
- excretes in **urine**
30
What is glucose and why is it essential?
A **small soluble simple sugar**
Essential for all cells for **respiration**
31
How do the kidneys control the concentration of glucose?
Kidneys **selectively reabsorbs glucose** to return it to the plasma
32
What are the kidneys 2 functions?
1. **filter waste materials out** of blood
2. Control the **water levels** o the blood
33
What are nephrons?
Thousand of **tiny tubes** in the kidney. They extend from the **renal Cortes into the renal medulla**
34
What are the 2 functions of nephrons?
- filtering the blood
- reabsorbing any useful substances
35
During filtration name 7 substances that are filtered out of the blood
- glucose
- ions - Na, K
- urea
- water
- oxygen
- amino acids
- carbon dioxode
36
What are the 3 substances that cant be filtered out of the blood and why?
- proteins
- red/white blood cells
- platelets
**too big**
37
During selective reabsorption what are the substances that are reabsorbed back into the bloodstream and what is the amount?
- **all** glucose
- **all** glucose
- **some** water
- **some** ions
38
What substance is not reabsorbed into the blood steam by selective absorption and why?
No **urea** is absorbed
**slightly toxic** + not useful
39
What substance does healthy urine contain
- urea
- **excess** water
- **excess** ions
40
What does healthy urine no contain**
- red/white blood cells
- glucose
- amino acid/ proteins
41
What process happens to excess amino acids in the liver?
**deamination**
Amino acids **broken down** into **urea**
42
What detects the water content of the blood?
Receptors in the hypothalamus (in the brain)
43
Which hormone controls the water level in the body and what does it act on?
ADH
Acts on the kidney tubules
44
What happens if the water content of the plasma is too low
- **ADH produced + secreted** by the **pituitary gland**
- this **increases permeability** of the **kidney tubules** to water
- causes **more water reabsorbed** back into water plasma by **kidney tubules**
- **less water** lost in **urine** - more concentrated
- blood water levels return back to normal
45
State the process when the water content of the plasma is too high?
- **pituitary gland** releases **less/no ADH**
- **decreases permeability** of kidney tubules to water
- **less water reabsorbed** by kidneys into blood
- **more water** lost in **urine** - more **diluted**
46
what does ADH stand for
Anti - Diuretic Hormone
47
what does kidney failure result in?
- **waste substances build up** in the blood and you lose ability to **control** the **levels of ions and water**
- can result in **death** as toxin, such as urea build up in the blood
48
kidney damage can occur as a result of:
- kidney infection
- genetic disease
- road traffic accident
49
why does dialysis have to done regulary?
to keep concentrations of **dissolved substances** in the blood at **normal levels**, and to remove waste substances
50
what is the dialysis machine consist of and why?
**partially permeable membrane** that is surrounded by **dialysis fluid**
- its is permeable to things like **ions and waste substances**, but not **big molecules** like proteins
- to mimic membranes in kidney
51
Dialysis fluid has the same concentration of what as in healthy blood and why?
same concentration of **dissolved ions and **glucose**
- prevents the net movement of glucose across the membrane as **no concentration gradient exists**
- means that useful **dissolved ions** and **glucose** won't be **lost from blood** during dialysis
- patient needs to retain glucose for **respiration**
52
does dialysis fluid contain urea and why?
No
- ** large concentration gradient** compared to blood
- means urea**diffuses** across partially permeable membrane from blood to dialysis fluid
- urea is toxic - essential to remove from patient blood
53
dialysis fluid contains what ion concentration level compared to the ideal blood plasma concentration and why?
- ion concentration **similar** to the ideal blood
- patients blood **too low in ions** : diffuse from the **dialysis fluid --> blood**
- patients blood **too high in ions** : diffuse from **blood --> dialysis fluid**
54
describe the process of how dialysis works
1. blood **leaves arm** through an artery
2. blood passes through a **pump** that **maintains blood pressure** to ensure blood continues to flow
3. **anticoagulants** added to prevent clotting
4. **thinned blood enters** dialysis machine
5. blood passes over **dialysis membrane**
6. **dialysis fluid** flows in the **opposite** direction to **blood** (counter current system)
- allowing **exchange** to occur between the two where a **concentration gradient** exists
7. **waste materials removed** as they move down the concentration gradient:
- all urea removed - diffusion
- excess ions - diffusion
- excess water - osmosis
8. **glucose** not removed - dialysis fluid and blood have same concentration so **no diffusion gradient**
9. filtered blood continues to flow through system to a **bubble trap** (gets rid of bubbles)
- filtered blood returns to patient
55
what are the advantages of a dialysis machine?
- can but patient **valuable time** if kidney donor not found
- **widely available** to all kidney patients (no shortage)
56
disadvantages of dialysis
- requires sessions of **3-4 hours** for **3 times a week** - very time consuming
- may cause **blood clot** or **infection**
- very **expensive**
57
what is the only cure for kidney failure?
kidney transplant
58
who can donate a kidney
- close relatives - higher chance of tissue match
- strangers with tissue match
59
why may the the donor kidney be rejected?
**antigens** on the surface of the **donor kidney cells** are recognised as **foreign** and causes immune system to **attack** donor kidney
60
what happens when a organ is rejected
**antibodies** of the **recipient attack the antigens** of donor kidney causing kidney **cell and tissue death**
61
how can the risk of injection be reduced?
- take **immunosuppressants** for life** - reduce risk of rejection but also reduce recipients ability to cope with all infectious diseases
- **tissue match** the organ that is donated - closer the tissue match less chance of rejection
62
what situation results in no risk of rejection?
**identical twin** - have the **same antigens** on their cell membranes
63
advantages of kidney transplant
- **normal life** with no regular trips to the hospital
- **long term cost is *low***
- **good success rate** - 80% if close tissue match
64
disadvantages of kidney transplant
- needs to take **immunosuppressants for life**
- Kidney only **lasts 8-9 years** on average
- **shortage** of suitable donors - long wating list
- **tissue matching** is essential
- donated organ must be **transplanted within *12 hours***
