1) This document provides definitions and information about animal anatomy and physiology. It discusses the levels of organization in living things from the chemical to the organism level. 2) Homeostasis and feedback mechanisms are explained. Negative feedback systems work to maintain stable internal conditions while positive feedback accelerates responses in some cases. 3) The document covers anatomical terminology used to describe animal structures and their positions relative to the body planes and midlines. Understanding this language is important for accurately describing anatomy.

1. DAMBI DOLLO UNIVERSITY
CNCS;
Animal Anatomy &
Physiology
Biol2095
for 2nd year Biotk Students’
Biotechnology Department
Delivered by ; Yidnekachew k.(MSc. in Biotechnology)
1

2. 1. Introduction
Definitions
Anatomy
 Anatomy (derived from Greek words meaning
“to cut open”) is the study of the morphology,
or structure, of organism.
Physiology
 The study of the functions of living things
biophysical, and biochemical processes

3. Fields of Anatomy
 Macroscopic (Gross anatomy)
 Microscopic anatomy
 Developmental anatomy
 Applied anatomy

4. Gross anatomy
 Seen with naked eye
 Study all the structure, such as nerves, bones, muscles, and blood
vessels, in defied regions such as head.
 Systemical - the study of a given organ system such as muscular or
skeletal systems. It also involves the study of a group of organ
working together for specific function, such as digestive and urinary
system.
 Regional– a surface anatomy considers markings that are visible
from the out side.

5. Microscopic Anatomy
 Viewed with a microscope
 Includes cytology and histology
Cytology: The study of the structure of individual cells that
constitute the smallest unit of life, at least in the sense of animal
Physiology.
Histology: The study of the four basic types of tissues.
 Tissues are a collection of a specialized cells and their
product that perform specific function

6. Developmental anatomy
 The study of the changes in structure and that occurs
throughout life.
 Embryology is a subdivision of developmental anatomy that
traces the developmental changes prior to birth. Many systems
of the body are not completely developed at birth, hence the
need to continue to follow their development after parturition.

7. Nomenclatures for Systematic Anatomy

8. Physiology
Cellular physiology
 The study of how cell works. This includes the study of
events at the chemical, molecular and genetic level.
Organ physiology
 Includes the study of specific organs, that is, cardiac or
ovarian.
System physiology
 Includes the study of the function of specific systems
such as the cardiovascular, respiratory, or reproductive
system.

9. Level of Organization
Chemical
level
Cellular level
Tissue level
Organ level
Organ system
level
Organism level

10. Chemical
level
Atoms are the smallest units of
matter that have properties of an
element.
They combine with covalent bonds
to form molecules such as molecular
oxygen (O2), glucose (C6H12O6),
or methane (CH4).
The properties of various
chemicals have a major influence on
physiology.

11. Cellular
level
As the smallest units of life, cells
have various sizes, shapes, and
properties that allow them to carry
out specialized function.
Some cells are cilium that allow
them to move carry out specialized
functions (i.e., the epithelial linings
the bronchioles or cells lining the
oviduct), where as other cells are
adapted to store lipids, produce
collagen, or contract when
stimulated.

12. Tissue
level
Tissue is a group of
cells having a common
structure and function.
The four types of
tissues includes
muscle, epithelial,
nervous, and
connective tissues.

13. Organ
level
Two or more tissues
working for a give function
form an organ.
All four tissue types
combine to form skin, the
largest organ of the body,
or the cochlea in the ear,
the smallest organ of the
body.

14. Organ system
level
Organs can work together
for a common function.
 The organ system
include the Integumentary,
skeletal, digestive,
lymphatic, muscular,
nervous, endocrine,
respiratory, urinary, and
reproductive systems.

15. Organismal
level
The organismal level,
or the whole animal,
includes all of the organ
systems that work
together to maintain
homeostasis.

16. Homeostasis
 According to American physiologist Walter Cannon (1932) meaning
“unchanging” internal environment.
 Fundamental to understanding physiology of various internal
conditions, such as plasma glucose, electrolyte concentration and
body temperature maintained.
 Animal maintain their internal environment by behavioral and
physiological mechanism.
 Behavioral - shifting from sunny to shady
 Physiological - increase in sweating to accomplish the same goal

17.  Homeostatic regulatory mechanisms consists of either negative
or positive feedback system.
 Negative feedback system are far more common than positive
feed back system.
Feedback system

18. Stimulus Physiological
Response
Adjustment
Decreased
environmental
temperature
Constriction of
blood vessels in
skin-hairs on body
erect shivering
Heat is conserved
more heat is
generated by
increased
metabolism
Increased
environmental
temperature
Dilation of blood
vessels of skin-
sweating
Heat is dissipated

19. Control Systems
 Most homeostatic systems are extrinsic: they are controlled from
outside the body. Endocrine and nervous systems are the major
control systems in higher animals.
 The nervous system: depends on sensors in the skin or sensory
organs to receive stimuli and transmit a message to the spinal cord or
brain.
The endocrine system: is the second type of extrinsic control, and
involves a chemical component to the reflex. Sensors detect a change
within the body and send a message to an endocrine effector
(parathyroid), which makes PTH.
Extrinsic

20. Control Systems
Intrinsic
 Local, or intrinsic, controls usually involve only one organ or
tissue. When muscles use more oxygen, and also produce more
carbon dioxide, intrinsic controls cause dilation of the blood
vessels allowing more blood into those active areas of the
muscles. Eventually the vessels will return to "normal".

21.  Negative feedback control mechanisms: (used by most of the
body's systems) are called negative because the information caused
by the feedback causes a reverse of the response.
 Positive feedback control: is used in some cases. Input
increases or accelerates the response.
Feedback mechanism

22. Negative feedback control mechanisms
 In negative feedback system, the control system initiates
changes that neutralize the stimulus.
 This either reduces or eliminates the stimulus, there by re
establishing the variable near its set point to maintain
homeostasis.

23. Example of negative feedback system
Body temperature regulation
 Every animal has a set point for body temperature, with the control center
residing in the hypothalamus, a region of the brain. When the body
temperature of an animal rises, possibly due to exposure to the sun, the
warmth receptors located in the skin and hypothalamus sense a rise in
temperature and send a signal to the hypothalamus. Hypothalamus
compares these signals to the set point and then activates heat losses
mechanisms (effector) such as sweating and vasodilatation. Sweating
results in evaporative cooling, while vasodilatation increases the blood flow
to the skin where heat is lost to the environment through radiation,
conduction, and conviction. The effector response results in decrease in
temperature back towards the set point.

24. Positive feedback control
 Biochemical control where the accumulation of the product
stimulates production of an enzyme responsible for that
product's production.
 positive feedback control occurs when information produced
by the feedback increases and accelerates the response.
 positive feedback systems are rare, their is situations where
they prove beneficial.

25. Example of positive feedback system
Uterine contraction
 Near the time of parturition, during uterine contraction, oxytocin is
produced. Oxytocin causes an increase in frequency and strength of
uterine contraction. This in turn causes further production of
oxytocin, etc.
 In case of blood clotting, an injured blood vessel secretes factors
that attract platelet to that site. These platelets secrete factors that
attract more platelets, and thus a positive cascade begins to occur.

26. Anatomical nomenclature
 As with any field of science anatomy has its own language
 It is necessary to know this language to describe and accurate
manner.
Cranial: is a directional term meaning toward the head. The neck is
cranial to the tail; it is closer to the head than is the tail.
Caudal: means toward the tail. The tail is caudal to the head.
Rostral and caudal: are directional terms used in reference to features
of the head to mean toward the nose (rostral) or toward the tail
(caudal).

27. The median plane: is an imaginary plane passing through the body so
as to divide the body into equal right and left halves. A beef carcass
is split into two halves on the median plane. The median plane is
sometimes called the midsagittal plane.
A sagittal plane: is any plane parallel to the median plane.
A transverse plane: is at right angles to the median plane and divides
the body into cranial and caudal segments. A cross-section of the
body would be made on a transverse plane. The cinch of a saddle
defines a transverse plane through the thorax of a horse.

28. A horizontal plane: is at right angles to both the median plane and
transverse planes. The horizontal plane divides the body into dorsal
(upper) and ventral (lower) segments. If a cow walks into a lake
until the water comes above the chest, the surface of the water is in a
horizontal plane in relation to the cow.
Medial: is an adjective meaning close to or toward the median plane.
The heart is medial to the lungs; it is closer to the median plane than
are the lungs.
Lateral: is the antonym of medial; it means away from the median
plane. The ribs are lateral to the lungs, that is, farther from the
median plane.

29. Lateral: is the antonym of medial; it means away from the median
plane. The ribs are lateral to the lungs, that is, farther from the
median plane.
Dorsal: means toward or beyond the backbone or vertebral column.
The kidneys are dorsal to the intestines; they are closer to the
vertebral column.
Ventral: means away from the vertebral column or toward the mid
abdominal wall. The udder is the most ventral part of the body of a
cow, the part of the body farthest from the vertebral column.

30. Deep and internal: indicate proximity to the center of an anatomical
structure. The humerus (arm bone) is deep in relation to all other
structures in the arm.
Superficial and external: refer to proximity to the surface of the body.
Hair is superficial to all other structures of the body.
Proximal: means relatively close to a given part, usually the vertebral
column, body, or center of gravity. Proximal is generally used in
reference to an extremity or limb. The carpus or knee is proximal to
the foot. farther from the vertebral column
Distal: means, and like proximal, it is generally used in reference to
portions of an extremity. The hoof is distal to the carpus or knee.

31. Palmar: Below the proximal ends of the carpus, palmar replaces
caudal.
 Example:- the dewclaws are on the palmar surface of the
forelimb.
Plantar: Below the proximal end of the tarsus, plantar replaces
caudal.
 Example:- the dewclaws of the hind limb are on the plantar
surface of the foot.

32. Directional terms and planes of the animal body

33. Directional terms and planes of the animal body

34. Directional terms and planes of the animal body
Horizontal plane