The Respiratory System

The Respiratory System

• Respiration

 

The respiratory system allows intake of oxygen to, and removal of carbon dioxide from the body via the lungs
The intake of oxygen and expulsion of carbon dioxide is known as gaseous exchange
Air is taken in through the mouth. It passes through the pharynx and larynx to the trachea
The trachea is kept open by rings of cartilage
The trachea splits into two bronchi that lead into each lung. The bronchi split into bronchioles which eventually end in air sacs called alveoli

• Alveoli are surrounded by capillaries. Gaseous exchange of carbon dioxide and oxygen take place in the alveoli when CO2 pass from the capillaries to the alveoli and O2 passes from the alveoli to the capillaries.


• The lungs are protected by the rib cage. The diaphragm lies below the lungs and moves downwards to allow the lungs to expand when an animal inhales air

The Skeleton

The Skeleton

• Functions of the skeleton
  Support
  – to give the body shape and support soft tissues
  Protection
  –some organs such as the brain, heart and lungs are protected by the skeleton
  Movement
  –muscles are attached to bone
  Mineral storage
  Production of red blood cells


• Structure of Bone
  Joint
  –A place where two or more bones meet
  Cartilage
  –A layer of tissue found on bones between joints which reduces friction
  Spongy bone
  –Responsible for production of red blood cells
  Medullary cavity
  –Produces white blood cells
  Compact bone
  – The outer layer of bone which is hard


• Connective Tissue
  Adipose tissue
  – Its main function is to store fat. It is also used for insulation
  Tendons
  – Connect muscle to bone. Inelastic fibers made of collagen
  Ligaments
  – Connect two bones together at a joint. Also made of collagen
  Muscular tissue
  –Muscles cause movement in the body when they contract


• Muscle Types
  Skeletal muscle
  –Voluntary muscle attached to bones
  –It is under conscious control
  –Example: muscles in legs
  Smooth muscle
  –Involuntary muscle that lines internal organs such as the oesophagus
  Cardiac muscle
  –Involuntary muscle that does not fatigue
  –Found in the heart

The Nervous System and endocrine

• The Nervous System

The nervous system in vertebrate animals consists of two parts:
–Central Nervous System (CNS)
–Peripheral Nervous System (PNS)
The central nervous system consists of
–The brain
–The spinal cord
The peripheral nervous system consists of
–Sensory nerves
–Motor nerves
A nerve cell is called a neuron.

• The Nervous System
  This allows an animal to detect what is going on in the world around it.
  It includes the brain, the spinal chord and the nerve cells.
  The nervous system controls receptors such as the eye and the ear and it also control the effectors the most important of which are muscles.


• The Endochrine System


• The Endochrine System


• 


• This is the hormone system in the body.
  Hormones are produced in very small quantities, transported by the circulatory system to specific parts of the body, where they can stimulate or inhibit actions in the target organ or tissue.
  Hormones are produced in many parts of the body e.g. the pituitary gland, the thyroid glands, the parathyroid glands, the pancreas, the adrenal glands and the gonads.


• Milk Let-Down
  External factors such as the sight or sound of a calf or entering the milking parlour and being having teats rubbed.
  This sends a message to the brain which cause the hormone oxytocin to be produced by the pituitary gland.
  This message is carried in the blood to the udder causing milk alveoli to contract releasing milk.


• Endocrine Glands
  The pituitary gland is located at the base of the brain.
  Some of the hormones produced by the pituitary are growth hormone, prolactin, luteinising hormone (LH), follicle stimulating hormone (FSH) and oxytocin.
  Oxytocin is responsible for milk let down and contractions during birth.


• Thyroid glands
  –Located in the neck and produce thyroxine which regulates metabolism in the body and is responsible for growth
  Parathyroid glands
  –Located on the surface of the thyroid glands. They release parathyroid hormone which regulates calcium levels in the bones and blood.
  The Pancreas
  –Secretes insulin into the bloodstream when there are high levels of glucose in the body. The liver and muscle cells take up the glucose. Glucose is stored as glycogen in the liver.
  Adrenal glands
  –Produce adrenalin when the body is under stress.


• Sex Hormones
  Androgens are hormones responsible for male sex characteristics and are produced in the testis. Testosterone is an androgen
  Freemartin condition occurs in twin calves where one is male and the other is female. Hormones pass from the male to the female in the womb leaving the female infertile
  Ovaries secrete oestrogen and progesterone.
  Oestrogen promotes the sex characteristics in females.
  Progesterone allows for the growth of the uterus during gestation.

The Kidney and Urine Production

The Kidney and Urine Production

• The Kidney and Urine Production
  Blood arrives in the kidneys through the renal artery and leaves through the renal vein.
  Blood is filtered in the kidney, it removes harmful compounds and excess salts.
  The amount of water in the blood is also controlled
  Urine is formed in the kidney and passes to the bladder through the ureter.
  Urine leaves the bladder through the urethra.


• 


• Structure of the Kidney
  The kidney consists of tubules called nephrons.
  Nephrons are located in the cortex of the kidney.
  The Loop of Henle and Bowman’s Capsule are parts of the nephron.

Digestive Systems

Digestive Systems

• Mammalian Teeth
  Mammals have different teeth depending on what they eat.
  Herbivores have incisors for biting and premolars and molars for chewing grass.
  Carnivores have very large canines for ripping and tearing meat.
  Omnivores have a mixture of all teeth.

Foods
Chemicals found in foods include carbohydrates, fats, proteins, vitamins, minerals and water.
During digestion these foods are broken down into their different chemical components.
These chemicals are broken down further and absorbed.

• The Digestive System

 

The digestive system includes:
–Ingestion – taking in food.
–Digestion – breaking down food.
–Absorption – absorbing the nutrients.
–Assimilation – using the food.
–Egestion – eliminating the undigested food.

• Ingestion
  Physical and chemical digestion occurs in the mouth.
  When animals see or smell food they produce saliva from 3 pairs of salivary glands in the mouth.
  Saliva contains a slimy lubricating substance called mucus and an enzyme salivary amylase that breaks starch down to maltose.
  This mixing of food with saliva is called mastication and results in a bolus being formed which is swallowed.


• The Oesophagus
  food passes down a long tube called the oesophagus to the stomach.
  Rhythmical contractions of the muscles called peristalsis propel the bolus along.
  Birds have a special storage organ at the base of the oesophagus called the crop.


• The Birds Stomach


• 
  Part of the stomach of a bird is called the gizzard and it contains grit which the bird has swallowed.
  This grit along with muscle movement grinds hard foods such as cereal grains.


• Rabbit and Pig Stomachs


• 
  There is only one chamber in these stomachs and so they are called monogastrics.
  Digestive juices are produced such as hydrochloric acid, pepsin and rennin.
  Rennin is very important in young animals as it digests milk protein.
  Food enters the stomach through the cardiac sphincter and leaves through the pyloric sphincter.


• Digesting Cellulose
  Cellulose is a valuable food source if it can be digested.
  Some animals are able to digest cellulose by culturing bacteria, that live in their digestive system, and digest the cellulose for them.
  One of these groups have normal stomachs and long intestines with micro organisms in the hind gut. They are called hind-gut fermenters e.g. rabbits and horses.
  The second group have a specialised stomach with four chambers and are called ruminants e.g. sheep and cows


• Herbivores with monogastric stomachs ferment their food in the large intestine and the appendix.
  This fermentation (anaerobic respiration) digests the cellulose.


• The Ruminant Stomach


• 
  The stomach consists of four chambers:
  –The rumen – contains anaerobic bacteria and protozoa that digest cellulose. Ruminants also digest some of the micro organisms and get protein from them.
  –The reticulum – has a honeycomb wall and digests food further before it is passed back to the mouth for further mastication.
  –The omasum – cud enters here and water is squeezed out and absorbed, solids pass to fourth chamber.
  –The abomasum – like the normal stomach of a monogastric where digestive juices are produced. Calves send milk straight to the abomasum where it is digested by rennin.


• The Small Intestine
  The first part of the small intestine is called the duodenum.
  Bile, produced in the liver, is added to food here and helps break down fat.
  Pancreatic juices, produced in the pancreas, contains a number of enzymes including pancreatic amylase that breaks down starch.
  Pancreatic juices are also added in the duodenum and further break down the food.


• Further along the small intestine intestinal juice, which contains the enzymes sucrase (breaks down sucrose) and lactase (breaks down lactose), are added.
  The internal surface of the small intestine is called the ileum. It has villi that increase its surface area and help absorption of nutrients


• 


• The Liver: Functions
  Production of bile to emulsify fats and lipids
  Storage of glucose in the form of glycogen.
  Storage of Vitamins A,D,E,K
  The breakdown of toxic substances
  –Ammonia is converted to urea
  The breakdown of red blood cells
  Temperature regulation

The Circulatory System, Blood and The Lymphatic System

The Circulatory System

• Consists of the heart, a pumping organ.
  Veins carry blood to the heart.
  Arteries carry blood away from the heart.
  Capillaries are narrow tubes that connect arteries and veins.

Functions of the Circulatory System

 

1. To carry digested food from the small intestine to all areas in the body which need it.


2. To carry oxygen from the lungs to the rest of the body.


3. To aid in the disposal of all wastes from the body.


4. To distribute heat.


5. To fight diseases by using white blood cells to fight off infection.

 

• Differences between Arteries and Veins
  

  Arteries and Veins have many differences:

  
  
  Arteries:                carrys blood away from the heart.


• 2.    Have thick muscular walls


• 3.    Have a pulse


• 4.    Deep under the skin


• 5.    Have no valves


• 6.    Arteries branch at their ends, into tiny arterioles those then join capillaries.

• Veins         :


• 1.    - Carry blood to the heart. 


• 2.    Have thin walls


• 3.    Do not have a pulse   


• 4.    Near surface of the skin


• 5.    Have valves to stop back-flow of blood.


•    6.    Veins branch at their beginnings into tiny venules which join capillaries.


• 


• Blood Flow
  Blood enters the right atrium through the venae cavae.
  From the right atrium the blood enters the right ventricle.
  From here it flows to the lungs in the pulmonary artery.
  From the lungs the blood enters the left atrium through the pulmonary vein.
  The blood goes from the left atrium to the left ventricle.
  The left ventricle is the main chamber of the heart and blood is pumped from here to the rest of the body through the main artery called the aorta.

 

• Composition of the Blood
  Blood is made up of 4 different substances:
  1.Plasma – this is the liquid part of the blood and is about 90% water
  2.Red Blood Cells – these contain haemoglobin and carries oxygen around the body.
  3.White Blood Cells – these cells fight infection.
  4.Platelets – these cells are involved in clotting the blood


• Functions of the Blood
  1. Transportation :The blood transports substances around the body.
  2. Immunity : The blood helps our body to fight infection.
  3.The blood forms clots that stops us from losing all our blood if we are cut


• Hepatic Portal System
  The hepatic portal vein carries blood from the intestine to the liver.
  The hepatic vein carries blood from the liver to the heart.


• Functions of the Liver
  1.Regulates the amount of glucose (sugar) in the blood in conjunction with the hormone insulin.
  2.Regulates the level of lipids (fats).
  3.Breaks down excess amino acids to ammonia and then urea.
  4.Produces bile which helps break down fats.
  5.Regulates body temperature.
  6.Stores vitamins and minerals.


• Regulation of Body Temperature
  Animals can keep the body warm by movement, wool, hair, respiration
  Animals can keep the body cool by lying in a shaded area, sweating, rolling in mud (pigs)
  Critical Temperature
  –The upper critical temperature is the point at which an animal needs to use energy to cool down
  –The lower critical temperature is the point where an animal uses energy to keep warm
  Optimum production levels are within the upper and lower range
  Age, weight, feed intake, feed type, building type, insulation and flooring affect critical temperature.


• The Lymphatic System
  The Lymphatic system absorbs fluid that has diffused from blood capillaries. It transports it to larger lymph vessels and eventually empties into the subclavian vein, which brings it to the heart.
  Lymph nodes (found along lymphatic vessels) and bone marrow produce lymphocytes
  –Lymphocytes are types of white blood cells needed for immunity
  –They act as a filter in the lymphatic system removing infectious organisms such as bacteria from lymph.It transports lymph around the body


• Functions:
  –To collect excess tissue fluid and return it to the bloodstream
  –To absorb fats from the intestine and transport them to the bloodstream
  –To defend the body against disease


• .Immunity
  Immunity is the ability of an organism to resist disease through the use of antibodies and white blood cells in response to exposure to the disease.
  
  
  
  • Active Immunity (animal produces its own antibodies – long term)
  
  
  
  –Natural Active Immunity - acquired when the body is infected by bacteria or virus. The body produces antibodies to fight the infection. They provide protection against the disease in the future.
  –Artificial Active Immunity - acquired artificially by means of vaccination.
  
  
  
  • Passive Immunity (animal receives antibodies – short term)
  
  
  
  –Natural Passive Immunity - acquired when antibodies are passed through mother’s milk or across the placenta.
  –Artificial Passive Immunity – acquired when antibodies are injected into the animal.

Animal Classification

• The Invertebrates


• Invertebrates are animals with no backbone.
  A species is a group of closely related organisms which interbreed and produce fertile offspring e.g. horses, dogs, cats, humans etc.
  There are between one and two million species.
  Based on a system proposed by Linnaeus each species is given a unique name e.g. for horses it is caballus
  Related species are grouped into a genus e.g. for horses it is Equus
  So the name of the horse is Equus caballus


• Genera are placed in families.
  Families are grouped into orders.
  Orders are grouped into classes.
  Related classes are grouped into a phylum.
  We will look at seven phyla that affect agriculture.

• CLASSIFICATION
  Kingdom
  Phylum
  Class
  Order
  Family
  Genus
  Species


• CLASSIFICATION
  Kingdom
  PHYLUM
  CLASS
  ORDER
  FAMILY
  GENUS
  SPECIES


• HUMAN CLASSIFICATION
  Kingdom- Animalia
  Phylum- Chordata
  Class -Mammalia
  Order -Primatia
  Family- Hominidae
  Genus- Homo
  Species -sapiens
  Homo -sapiens

 

• Phylum Protozoa
  Single celled animals, microscopic.
  Protozoa that produce spores cause diseases in humans and animals.
  Babesia causes redwater fever in cattle and is transmitted by a blood sucking tick (Ixodes ricinus)
  The spores cause red blood cells to burst and haemoglobin is released and passed in the urine, hence redwater.

 

• Phylum Platyhelminthes
  This group contains flat worms, two groups of which are very important to Irish agriculture:
  –Flukes (See book pg. 250 -253)
  –Tapeworms (See book pg. 253)


• Control of Liver Fluke
  The liver fluke can be controlled in a number of ways:
  –Dose cattle/sheep with an anthelmintic which kills the flukes
  –Drain land to get rid of mud snail
  –Fence off wet areas to keep cattle/sheep away from infected areas
  –Use molluscicides to kill snails
  –Introduce geese to control mud snail population


• Phylum Nematoda
  Includes nematodes, eelworms and roundworms.
  Round, not segmented, elongated, pointed at either end and vary from a few mm to 15cm long.
  Life Cycle: eggs passed in faeces of host; hatch into larvae; larvae are eaten and cycle begins again.
  Important examples of nematodes are stomach and intestinal worms, lungworm and potato eelworm.


• Phylum Annelida
  Includes the earthworm, Lumbricus terrestris, and also leeches and marine worms.
  Earthworms are round, segmented and have four pairs of bristles on each segment.
  Earthworms feed on organic matter and excrete worm casts.
  They are very important for soil fertility and structure.


• Phylum Mollusca
  Slugs (no shell) and snails are the most important members.
  They contain a foot that secretes mucus used for crawling and they have a special tongue called a radula.
  Slugs tend to be a problem in horticultural crops where they eat the vegetation.
  Most important member is the secondary host of the liver fluke the mud snail, Lymnaea truncatula


• Phylum Arthropoda
  90% of all animals are in this phylum.
  They have an external skeleton, joined appendages and in order to grow they moult.
  Class Arachnida includes spiders, mites and ticks. These have two body segments and four pairs of legs. Mange mite and the sheep tick are the most important in this group.
  Class Insecta includes lice, fleas , aphids, cranefly (larvae is a leatherjacket) butterfly and clickbeetle (larvae is a wireworm). These have three body segments, three pairs of legs and usually two pairs of wings.


• Life Cycle of Class Insecta
  Complete metamorphosis:
  –Eggs -> larva -> pupa -> adult
  The larva is the feeding stage and the pupa is the resting stage. Some larvae are pests e.g. wireworm and leatherjackets eat crops.
  Aphids suck sap from plants damaging them directly and they may damage them indirectly by transferring virus diseases.

 

• Common Insect Pests and their Larva
  Insect: Crane Fly
  Larva: Leatherjacket
  Insect: Click Beetle
  Larva: Wireworm


• Parasites
  Parasites are species that live at the expense of other organisms.
  Ectoparasites live on the outside of the host and often have claws (lice) and sucking mouthparts (aphids, ticks) to hold on.
  Endoparasites live inside the host and have a special coating called a cuticle which protects them from the hosts defences e.g. fluke, tapeworms, hoose.


• Phylum Chordata
  Vertebrates are animals with a backbone and they belong to phylum Chordata.
  In this phylum are birds and mammals.
  Birds and mammals are the only warm blooded animals.
  This means their body temperature is independent of, and often much higher than, the surrounding environment.


• Birds – Class Aves
  Birds have wings, feathers and specially lightened bones.
  They do not have teeth but have a beak instead.
  In order to reproduce they lay eggs.


• Mammals – Class Mammalia
  Mammals have hair.
  Mammals give birth to live young.
  Mammals nourish their young in the womb via a placenta.
  When the young are born they feed on milk from the mothers mammary gland.
  Ungulates is a word to describe hooved animals.


• Dental Formulas
  Pig 3 1 4 3 Upper Jaw
  3 1 4 3 Lower Jaw
  Sheep 0 0 3 3 Upper Jaw,  3 1 3 3 Lower Jaw
  Rabbit 2 0 3 3 Upper Jaw
  1 0 2 3 Lower Jaw